Detailed explanations in West Bengal Board Class 8 Geography Book Solutions Chapter 2 Unstable Earth offer valuable context and analysis.

WBBSE Class 8 Geography Chapter 2 Question Answer – Unstable Earth

Multiple Choice Questions & Answers : (1 mark for each question)

Question 1.
J. T. Wilson introduced the word ‘Plate’ in-
i) 1965
ii) 1906
iii) 1970
iv) 1955
Answer:
i) 1965

Question 2.
Machenziae and Parker gave information on plate movement in-
i) 1967
ii) 1990
iii) 1965
iv) 1960
Answer:
ii) 1965

Question 3.
The vivid explanation of the plate tectonic theory was given by-
i) W. J. Morgan
ii) J. T. Wilson
iii) Alfred Wegener
Answer:
i) W. J. Morgan.

Question 4.
Asthenosphere lies –
i) 500-600 km below the crust
ii) 300-400 Km below the crust
iii) 200-300 kmbelow the crust
iv) 100-200 Km below the crust.
Answer:
iv) 100-200 Km.

Question 5.
Krakatua volcano has become active after-
i) 200 years
ii) 400 ycars
iii) 500 years
iv) 300 years
Answer:
i) 200 years.

Question 6.
The percentage of active volcano in the earth-
i) 10%
ii) 15%
iii) 20%
iv) 30%
Answer:
ii) 15%

Question 7.
The percentage volcanocs of the world are located in the middle of the plate on hot spot About-
i) 2%
ii) 3%
iii) 5%
iv) 8%
Answer:
iii) 5%.

Question 8.
The focus of the earthquake is located at the depth of –
i) 50-100 Km
ii) 100-150 Km
iii) 150-300 Km
iv) 200-250 Km
Answer:
i) 50-100 Km.

Question 9.
San Francisco was almost completely destroyed in a devastating earthsuake in-
i) 1910
ii) 1912
iii) 1904
iv) 1906
Answer:
1906

Question 10.
Percentage of earthquakes on the earth occur in the Pacific belt
i) 60%
ii) 70%
iii) 20%
iv) 40%
Answer:
ii) 70%.

Question 11.
Every year the powerful volcanic activities in the continental area are more than-
i) 20
ii) 10
iii) 40
iv) 50
Answer:
iv) 50.

Question 12.
The eruption of mount Pole occured in-
i) 1906
ii) 1202
iii) 1908
iv) 1905
Answer:
i) 1906.

Question 13.
Enormous loss of life and property took place due to the eruption of Mount St Helen in-
i) 1975
ii) 1980
iii) 1991
iv) 1900
Answer:
ii) 1980.

Question 14.
At the time of eruption many people die for-
i) cancer
ii) asthma
iii) suffocation
Answer:
iii) suffocation.

State whether True or False : (1 mark for each question)

1. The earth crust is made up of 18 small plate.
2. The outer mantle is located 300-400 Km. deep under the earth crust.
a. The temperature of asthenosphere is 1500° C.
4. The fold mountains are called ‘Young’.
5. The tectonic plates moved on asthenosphere.
6. popa of Mayanmar is a active volcano.
7. Primary wave is the fastest seismic wave and reaches the earth’s surface before all other waves.
8. The interior of the earth is still very hot.
9. Example of old fold mountain is Rocky.
10. Volcanism and earthquake are examples of sudden earth novements.
Answer:
1. false
2. false
3. true
4. true
5 true.
6. false
7. true
8. true
9. false
10. true.

Fill in the blanks : (1 mark for each question)

1. The temperature of asthenosphere is _______.
2. ______ is the deepest trench of the earth.
3. The divergent plate margin is called _______ plate margin.
4. The mountains are formed more than ______ years ago.
5. When the magma flows on the earth crust it is called ______.
6. The mountains like Himalaya Alps are formed ______ lack years ago.
7. ______ of earth is active volcano.
8. _______ is an alternative source of energy.
9. The epicentre of earthquake is ______ km deep.
10. In year ______ earth quake occur in
11. In 1906 the magnitude of the earthquake was _______.
12. ______ city was destructed in earthquake.
13. Earthquake takes place in earth at _________.
14. _____people had lost their life in Tsunami.
15. Damage and destruction was caused in ______ countries of South-East Asia.
16. On 26th January 2001 in _______ of Gujarat almost one lakh people lost their lives for severe earthquake.
17. Sudden of ______ earth the houses are broken.
18. Most of the active _______surround Pacific ocean as a ring.
19. The ring of earthquake in India is generally _________.
20. The magnitude of earthquake is measured by _________.
21. From the epicentre of the earthquake two types of wave spread out along the _____
22. Almost each and every ______ is earthquake prone.
23. Most of the focus of the earth quake located at the depth of _______ km.
24. ________ of N.ars is the highest voleanoes of the solar system.
25. A type of dense viscous lava comes out from the volcanoes of Indonesia which is known as _____ in Hawaiean language.
Answer:
1. 1500° C
2. Mariana
3. constructive
4. 3 – 4 millions of years
5. lava
6. 40
7. 15% Neutron
8. Geothermal energy
9. 50-100
10. 1955 kolce of Japan
11. 8.5
12. Sunfrancisco
13. 20%
14. 36000
15. 111
16. Bhuj
17. temor
18. Volcanoes
19. Himalaya mountain region
20. Seismograph
21. earth crust
22. margin of the plate
23. 50-100
24. Olympus Mars.
25. Aa.

Match the column A with column B.

Columu A	Column B
a. There are 6 major	i. at a rate of 10 cm/year
b. The earth’s crust is made of	ii. occur in Pacific Ring of Fire
c. Sometimes two plates move towards	iii. and 20 minor plates
d. Pacific Ocean plate is moving	iv. cannot be forecasted
e. The interior of the earth	v. due to an earthquake
f. 70 percent of all earthquake on the earth	vi. each other and collide
g. Unlike other natural disasters, an eartquake	vii. a few rigid and solid plates
h. Sometimes coastal land may be submerged	viii. is still very hot

Answer:
a) There are 6 major and 20 minor plates.
b) The earth’s crust is made of a few rigid and solid plates.
c) Sometimes two plates move towards each other and collide.
d) Pacific Ocean plate is moving at a rate of 10 cm / year.
e) The interior of the earth is still very hot.
f) 70 percent of all earthquake on the earth occur in Pacific Ring of Fire.
g) Unlike other natural disasters an eartquake cannot be forecasted.
h) Sometimes coastal land may be submerged due to an earthquake.

Very Short Questions & Answers : (1 mark for each question)

Question 1.
Which scientist introduced the term ‘Plate’?
Answer:
In 1960 Canadian geophysicist – J. T. Wilson introduced the term ‘Plate’.

Question 2.
Who gave information on plate movement?
Ans:
In 1967 Mekensil and Parker gave information on Plate movement.

Question 3.
Who gave vivid explanation of the Plate tectonic theory?
Answer:
In 1967 W. J. Morgan and Le Pichon gave vivid explanation of the plate tectonic theory.

Question 4.
What is the deepest trench of the world? In which ocean does it lie?
Answer:
The deepest trench in the world is Mariana trench. It lies in Pacific ocean.

Question 5.
How is Alps mountain formed?
Four in one (viii)-24
Answer:
Alps mountain is formed when African and Eurasian plates converged to each other.

Question 6.
Name the main fold mountain of the world.
Answer:
Most of the fold mountains of the world have formed for convergence of the continental plates. These are Applachian Ural Aravalli etc

Question 7.
What is Volcanic mountain?
Answer:
The mountains those are formed by deposition of volcanic material is called volcanic mountain. Example-Fujiyama of Japan.

Question 8.
When did the volcanism start?
Answer:
Volcanism started millions of years ago?

Question 9.
In which countries volcanism have occured?
Answer:
Volcanism have occured in Japan Italy India Indonesia etc.

Question 10.
How is the ‘process affecting earth’s crust’ is classified?
Answer:
The process affecting earth’s crust is classified into the types – (i) Endogenetic process (ii) Exogenetic process.

Question 11.
What is lava?
Answer:
The melted viscous substance of the earth’s interior is called magma and when it comes out on the earth surface it is called lava.

Question 12.
Which is the highest volcano of the solar system?
Answer:
Olympus Mons of the Mars is the highest (27 Km) volcano of the solar system.

Question 13.
What percent volcano on the earth is active?
Answer:
15% volcanoes on the earth is active.

Question 14.
What is earthquake?
Answer:
When energy trapped in the blastic interior of the earth is suddenly released the earth crust experience temors which is called earthquake.

Question 15.
In which year devastating earthquake occured?
Ans:
Devastating earthquake occured in 2004 300000 lives were lost and enormous damage causc d over 11 countries in south east Asia.

Question 16.
What is Seismograph?
Answer:
A Seisomograph is the instrument measuring the magnitude of an earthquake.

Question 17.
In which year earthquake occured in Chili?
Answer:
In 1960 earthquake occured in Chili.

Question 18.
What was the level of the scale of the earthquake of Chili??
Answer:
The level of the level of the scale was 8.5.

Question 19.
At what percent the earthquakes occur in the Mid Continental Belt?
Answer:
20% earthquakes occur in the Mid Continental Belt.

Question 20.
Name the volcanoes of ‘Pacific Ring of Fire’?
Answer:
The volcanoes of Pacific Ring of Fire are Fujiyama (Japan) Pinatubo (Philippines), Krakatau (Indonesia) St. Helen (USA) Popocate peti (Maxico) Cotopaxi (Equador) ete.

Question 21.
What is the similarity between volcanism and earthquake?
Answer:
Volcanism and earthquake are both sudden manifestations of endogenetic forces.

Question 22.
What contribute to an area being more prone to disasters?
Answer:
Worldwide increase of population unplanned urbanization construction of heavy multistoried buildings roads dams and reserviors and illegitimate mining – all contribute to an area being more prone to disasters.

Question 23.
How can earthquake form natural harbour?
Answer:
Due to earthquake sometimes coastal land may be submerged due to an earthquake thereby forming an natural harbour.

Question 24.
Give an example where mud island emerged from under the water due to earthquake.
Answer:
A ‘mud island’ has emerged from under the water off the Karachi coast.

Long Questions & Answers : (3 marks for each question)

Question 1.
Write a short note on voleanism.
Answer:
From the time of the creation of the earth the volcanic erruption is occuring for millions of years. At the time of volcanic erruption the hot matter materials ash gases etc comes out from the openings of the earth. After frequent erraption lava is accumulated around the mouth of the volcano forming a cone shaped mountain. This type of mountain is called volcanic mountain as it is formed by deposition of the volcanic material. For example – Fujiyama of Japan Vesuvious of Italy Barren of India Krakatoa of Indonesia. In different geological time the temperature of earth’s atmosphere has been controlled by the process of volcanisation and finally has reached present favourable condition.

Question 2.
How volcanism takse place?
Answer:
The interior of the earth is still extremely hot. Naturallyb rocks are supposed to melt in 2000° C temperature at mantle. But for the extreme pressure of the upper layer the melting point is increased. Thus the rocks melts partly become slipping and flows like plastic. In some part of outer mantle the rocks melts completely. The density of the melted rock is lower. It is lighter than other partially melted rocks of the surrounding. The pressure and the melting point of magma decreases proportionally with the rising upward of magma. The liquid portion of magma turns into gas and water vapours under extreme pressure. Then the magma comes out to the earth’s surface through the opening of earth crust.

Question 3.
How is the earth quake formed?
Answer:
Almost all plate margin in the earth are highly earthquake prone and so all the volcanoes and the centres of earthquake are lie at same place. Besides natural causes like tectonic slides earthquake can also occurs from artificial or non natural causes like digging of underground pits mines and tannels construction of reservoirs and bomb explosion.

Question 4.
What is Contiuental Drift Theory?
Answer:
According to the continental Drift Theory of Alfred Wegener-about 300 million years ago all the present day landmasses were united as a supercontinunt called pangea. Later on it began to break apart and the pieces direted in different directions. Actually the continental crust was floating over oceanic crust. But the Continental Drift Theory could not fully explain the causes of earthquake or formation of oceans countries and mountains volcanism.

Question 5.
What is the divergent plate margła?
Answer:
When two oceanic plates move away from each other hot molton magma comes upward from the earth’s interior and new oceanic crust and mid oceanic ridges are formed from the hot molten magma after getting cooled and solidified. This is called divergent plate margin.

Question 6.
What is Mariana trench?
Answer:
For the moving towards of each other of continental and oceanic plate heavy oceanic plate get submerged under the continental plate. As the result deep oceanic trench is developed in this way. Mariana trench of the Pacific is the deepest trench of the world.

Question 7.
What is divastating plate margin?
Answer:
When the molten materials come out from the interior along the plate margins several volcanoes and volcanic islands are formed along the subduction plate margin. As the earth quake and earth movements are the regular phenomena in this areas of the crust. This type of plate margin is called divastating plate margin.

Question 8.
What is Seismic waves?
Answer:
Energy generated by an eartinquake spreads out in the form of waves from the focus and the epicenter to other parts of the earth just like the radial surge of waves after a stone is dropped on water. These waves are called Seismic waves.

Question 9.
Classify the Seismic waves?
Answer:
Seismic waves are of three types.
a) Primary wave : It is the fastest seismic wave (6 Km / sec) and reaches the earth’s surface before all other waves. This wave travels through solid liquid and gaseous media through a push and pull process.
b) Secondary wave : It reaches the earth’s surface immediately after the primary wave (3-5 Km . sec ). This wave can not travel through liquid and gaseous media. It travels only through solids.
c) Surface waves or level waves: Two types of this wave (3-4 Km / sec) spread out from the epicenter of the earthquake along the eart’s surface. These waves are responsible for most of the damages caused by eartquakes.

WBBSE Class 7 History Question Answer West Bengal Board

WBBSE Class 7 History Book Solutions West Bengal Board in English Medium

• Chapter 1 The Idea of History
• Chapter 2 Some Aspects of Indian Political History: A.D. 7th Century to 12th Century
• Chapter 3 Some Aspects of Indian Society, Economy and Culture: A.D. 7th Century to 12th Century
• Chapter 4 The Delhi Sultanate: Turko-Afgan Rule
• Chapter 5 The Mughal Empire
• Chapter 6 Towns, Traders and Trade
• Chapter 7 Lifestyle and Culture: Sultanate & Mughal Era
• Chapter 8 The Crisis of the Mughal Empire
• Chapter 9 India Today: Government, Democracy and Self Governance

WBBSE Class 7 History Book Solutions West Bengal Board in Hindi Medium

• Chapter 1 इतिहास की अवधारणा
• Chapter 2 भारतीय राजनैतिक इतिहास की विभिन्न धाराएँ (700-1200)
• Chapter 3 भारतीय समाज, अर्थनीति एवं संस्कृति की विभिन्न धाराएँ (700-1200 ई०)
• Chapter 4 दिल्ली सल्तनत तुर्की अफगान शासन
• Chapter 5 मुगल साम्राज्य
• Chapter 6 नगर, व्यापारी और व्यवसाय
• Chapter 7 जीवन यात्रा और संस्कृति सल्तनत और मुगल काल
• Chapter 8 मुगल साम्राज्य का संकट
• Chapter 9 सरकार, गणतंत्र और स्वायत्त शासन

WBBSE Class 7 Solutions

WBBSE Class 8 History Question Answer West Bengal Board

WBBSE Class 8 History Book Solutions West Bengal Board in English Medium

• Chapter 1 The Idea of History
• Chapter 2 Rise of Regional Powers
• Chapter 3 Establishing the Colonial Authority
• Chapter 4 The Nature of Colonial Economy
• Chapter 5 Reaction of Colonial Rule: Co-operation and Revolt
• Chapter 6 The Beginning of Nationalism
• Chapter 7 Nationalist Ideals and Their Evolution
• Chapter 8 From Communalism to the Partition
• Chapter 9 Constitution of India: Democratic Structure and Citizen’s Rights

WBBSE Class 8 History Book Solutions West Bengal Board in Hindi Medium

• Chapter 1 इतिहास परिचय
• Chapter 2 प्रादेशिक शक्तियों का उत्थान
• Chapter 3 औपनिवेशिक सत्ता की प्रतिष्ठा
• Chapter 4 औपनिवेशिक अर्थनीति का स्वरूप
• Chapter 5 औपनिवेशिक शासन का प्रभाव, सहयोग और विद्रोह
• Chapter 6 राष्ट्रीयतावाद का प्रारंभिक विकास
• Chapter 7 भारत के राष्ट्रीय आंदोलन का आदर्श और परिवर्तन
• Chapter 8 साम्प्रदायिकता के कारण देश का विभाजन
• Chapter 9 भारत का संविधान गणतंत्र की रूपरेखा और नागरिकों के अधिकार

WBBSE Class 8 Solutions

WBBSE Class 7 Geography Question Answer West Bengal Board

WBBSE Class 7 Geography Book Solutions West Bengal Board in English Medium

• Chapter 1 Earth’s Revolution
• Chapter 2 Determination of the Location of a Place on the Earth’s Surface
• Chapter 3 Air Pressure
• Chapter 4 Landforms
• Chapter 5 River
• Chapter 6 Rock and Soil
• Chapter 7 Water Pollution
• Chapter 8 Soil Pollution
• Chapter 9 Continent of Asia
• Chapter 10 Continent of Africa
• Chapter 11 Continent of Europe

WBBSE Class 7 Geography Book Solutions West Bengal Board in Hindi Medium

• Chapter 1 पृथ्वी की गति
• Chapter 2 धरातल पर किसी स्थान की स्थिति का निर्धारण
• Chapter 3 वायु दबाव
• Chapter 4 भू-आकृति
• Chapter 5 नदी
• Chapter 6 चट्टान और मिट्टी
• Chapter 7 जल प्रदूषण
• Chapter 8 मिट्टी प्रदूषण
• Chapter 9 एशिया महादेश
• Chapter 10 अफ्रीका महादेश
• Chapter 11 यूरोप महादेश

WBBSE Class 7 Solutions

Detailed explanations in West Bengal Board Class 8 Geography Book Solutions Chapter 1 Interior of the Earth offer valuable context and analysis.

WBBSE Class 8 Geography Chapter 1 Question Answer – Interior of the Earth

Textbook Page no. 1

Question 1.
What lies underneath the hard surface on which we stand?
Answer:
There are different things lies underneath the hard surface. They are gold mine, coal mine, hat spring volcanoes etc.

Question 2.
Has anybody ever seen the interior of the earth?
Answer:
It is not possible to see the interior of the carth. But we can somehow feel the warm water of hot spring, gold mine. coal mine and from that we can estitaate a bit what may be in the interior of the earth.

Question 3.
How much one has to dig up to see the centre of the earth?
Answer:
One has to dig up 6370 km to see the centre of the earth.

Question 4.
How far has it be possible to know the interior of the earth?
Answer:
It has become possible to guess how is the interior of the earth.

Question 5.
Why does density vary in different layers of the interior of the earth?
Answer:
The density of substances that lie near the centre more. At the time of the creation of the earth more dense and hot substances accumulate near the centre of the earth due to the gravitational force. Specially iron and nickel rotate around the centre of the earth. Comperatively lighter substances like aluminium and silicon come upword. Generally more we go near the centre of the earth more we feel the pressure extended by the materials. So as the pressure increases the density also increased. Thus the density varies in different layers of the interior of the earth.

Textbook Page no. 2

Question 1.
Why can we not go near the centre of the earth?
Answer:
It is not possible to dig up 6370 km to go near thic centre of the earth !

Question 2.
Why couid we not collect any information directly about the earth’s interior?
Answer:
We can not enter in the earth’s interior easily. So it is not possible to collect information about earth’s interior directly.

Textbook Page no. 6

Question 1.
Explain the convection current in asthenosphere with the help of simple experiment.
Answer:
The layer of asthenosphere is very weak. Substances of this layer are molten and soft in nature. Due to exsessive heat and pressure the rocks are here in a state of viscosity-just like melted asphalt or molasses. Comperatively light materials come upwards when heated geothermally, and allow the heavier one to go downward. Thus the convection current occurs in asthenosphere.

Question 2.
what is the difference between magma and lava?
Answer:
Magma: Magma is the melted and liquid form of mixture of gas and vapour due to excessive pressure and temperature of earth chamber.
Lava: Lava is the loot molten semiliquid magma that comes out through the opening of earth surface.

Question 3.
You have an idea about the exterior and interior of the earth Which one attracts you more and why?
Answer:
I like the exterior of the carth as it is possible to be observed and analyzed.

Class 8 Geography Chapter 1 Question Answer West Bengal Board – Interior of the Earth

Multiple Choice Questions & Answers : (1 mark for each question).

Question 1.
The core of the earth is almost-
i) 3500 km
ii) 5300 km
iii) 6300 km
ii) 3700 km
Answer:
i) 3500 km.

Question 2.
The average temperature of core is almost-
i) 3000°C
ii) 4060°C
iii) 5000°C
iv) 6000°C
Answer:
iii) 5000°C.

Question 3.
In between 30-700 km of the mantle is known as-
i) nifesima
ii) crofesima
iii) outer core
iv) inner core
Answer:
ii) crofesima

Question 4.
Concard discontinuity is lying-
i) above SIAL
ii) below SIM
iii) between SIAL and SIMA
iv) below SIAL
Answer:
iii) between SIAI, and SIMA

Question 5.
The temperature of mantle is-
i) 1000°-2000°
ii) 3000°-4000°C
iii) ii) 4000°-5000° C
iv) 2000°-3000°
Answer:
iv) 2000°-3000°C.

Question 6.
The upper layer of the earth’s crust is-
i) SIMA .
ii) SIAL
Answer:
ii) SIAL.

Question 7.
The outer most part of the earth is very-
i) thick
ii) thin
Answer:
ii) thin.

Question 8.
Greater part of the earth consists of –
i) Hydrogen
ii) Oxygen
ii) Nitrogen
Answer:
ii) Oxygen.

Question 9.
The density of the matter near the centre of the earth is-
i) more
ii) less
Answer:
i) more

Question 10.
The earth originated almost-
i) 640 crore years ago
ii) 540 crore years ago
iii) 460 crore years ago
Answer:
iii) 460 crore years ago

State wliether True or False : (1 mark for each question)

1. It is an casy task to collect information of earth’s interior.
2. Temperature in carth’s interior increases at the rate of abott 10°C / 33 meters depth.
3. Regarding to the earth’s depth 12 km depth is negligible..
4. Lava comes out through the hot spring.
5. There is a pool of fire in the interior of the carth.
6. Sometimes there are severe treamous due to tremendous cyclone.
7. There are few countries where the electricity is generated from geothermal energy.
8. The volume of the matter increases with the increasing of the temperature.
9. SIAL lies above SIMA or oceanic crust.
10. Conrad discontiunity is lying in between SIAL and SIMA.
11. Greater part of the earth crust consists of Silicon.
12. The rocks of the earth crust is rich in minerals.
13. 47% of earth crust is covered with oxygen.
14. Scientists have found only two layers in the earth interior.
15. Mantle lies below the crust.
Answer:
1. false
2. false
3. true
4. false
5. true
6. false
7. false
8. true
9. true
10. true
11. false
12. true
13. true
14. fale
15. true.

Fill in the blanks : (1 mark for each question)

1. The earth’s _______ is divided into layers.
2. Scientist have collected information regarding earth’s interior by matching the movement of the _______ .
3. _______ discontinuity line lies in between mantle and core.
4. The _______ encircles the inner core.
5. The two layers composed of different elements and varied density determind by _______.
6. _______ is lying in between SIAL and SIMA.
7. The radius of the earth is _______ km.
8. The distance between earth-surface and the _______ is 6370 km.
9. World’s decpest gold mine located in _______ Africa is only 3-4 km deep.
10. Sometime the earth shakes for tremendous _______ .
11. The earth has been created almost _______ years ago.
12. Hot semi-liquid comes out through the mouth of _______ .
13. Hot spring is found at _______ in West Bengal.
14. _______ is one type of energy.
15. In many countries of the world _______ is genereted from heat energy.
16. _______ lulfils their 30% demand of electircity from geothermal energy.
17. The _______ generates more electricity from geothermal energy in the world.
18. The using of _______ can be reduced by using thermal energy to produce electricity.
19. The average density of the matter is _______ gram / cubic cm near the centre of the earth.
20. In respect of _______ satellites average density of the earth is 5.5 gram / cubic c m.
21. Theof _______ the matter near the centre of the earth is more.
22. _______ matter always precipitates underneath.
23. Light matters _______ upwards.
24. During the origin of the earth the very hot and denser matters move towards the earth’s centre due to _______ pull.
25. Especially ________ and Nickel start rotating the centre of the earth.
26. In general to pressure of _______ increases with the increase of depth towards earth’s interior.
27. Earth’s _____ is divided into layers of varied densities and characteristics.
28. Scientists have collected information regarding earth’s interior by watching the movement of the seismic ______.
29. The average depth of the carth’s crust is ____ km below the occeans and _____ km beneath the continents.
30. _______ lies over the SIMA or ocennic crust.
31. _______ of the crust are rich in various minerals.
32. _______ lies at the top of the crust.
Answer:
1. interior
2. seismic waves
3. gutenberg
4. Outer core
5. discontinuity line
6) Conrad discontiunity
7. 6700 km
8. core
9. South
10. earth quake
11. 460
12. Volcano
13. Bakreswar
14. Geo-thermal heat
15. electricity
16. Iceland
17, United States of America
18. fossil fuel
19. 11
20. artificial
21. density
22. Heavy
23. float
24. gravitational
25. iron
26. matters
27. interior
28. waves
29. 5 km and 60 km
30. SIAL
31. Rocks
32. Sail.

Match the following : (1 mark for each question)

a) Match the column A with column B.

Column A	Column B
a) Moho lies between	i) into layers like an onion
b) Uppermost layer is compared	ii) out of the carth’s interior
c) Conrad discontinuity	iii) near the surface
d) Earth’s interior is divided	iv) $5100 \mathrm{~km}$ to $6370 \mathrm{~km}$ deep
e) In hot springs boiling water emerges	v) the crust aud the mantle
f) Lighter elements float upward	vi) is between SIAL and SIMA
g) The inner core is nearly	vii) axis of the earth in semi-solid state
h) The outer core rotates around the	viii) with the skin of sn apple

Answer:
a) Moho lies between the crust and the mantle.
b) Uppermost layer is compared with the skin of sn apple.
c) Conrad discontinuity is between SIAL and SIMA.
d) Earth’s interior is divided into layers like an onion.
e) In hot springs boiling water emerges out of the earth’s interior.
f) Lighter elements float upward near the surface.
g) The inner core is nearly 5100 km to 6370 km deep.
h) The outer core rotates around the axis of the earth in semi-solid state.

Very Short Questions & Answers : (1 mark for each question)

Question 1.
What is the radius of the earth?
Answer:
The radius of the earth is 6370 km.

Question 2.
What is the distance between the surface and the core of the earth?
Answer:
6370 km. is the distance between the surface and the core of the earth.

Question 3.
What is the depth of the deepest mine of the world?
Answer:
The depth of the deepest mine of the world 3-4 km.

Question 4.
What is the rate of increasing temperature in the earth’s interior?
Answer:
The temperature in the earth’s interior increases at the rate of about 1°C / 33 meters depth,

Question 5.
Which is the artificial deepest hole of the world?
Answer:
The artificial deepest hole of the world is the hole in kala peninsula of north western Russia measuring a depth of 12 km.

Question 6.
What comes out from the hot spring?
Answer:
Hot water comes out from the hot spring.

Question 7.
What comes out form the mouth of the volcanoes?
Answer:
Hot molten semi-liquid lava comes out from the mouth of the volcano.

Question 8.
When was the earth created?
Answer:
The earth was created almost 460 crore years ago.

Question 9.
What sappens to the matter if the temperature is increased?
Answer:
On heating the solid matter converts into liquid and expands in volume.

Question 10.
Where in the earth the temperature and the pressure both are excessive?
Answer:
in the interior of the earth.

Question 11.
Where in West Bengal hot spring is situated?
Answer:
Hot spring is situated at Bakreswar of West Bengal.

Question 12.
What is called this type of water?
Answer:
This type of water is called ground water.

Question 13.
What is geo-thermal heat?
Answer:
Geo-thermal heat is one type of energy.

Question 14.
What can be generate from geo-thermal energy?
Answer:
Electricity can be generated from geo-thermal energy.

Question 15.
What percent of the demand of electricity is fulfilled from geo-thermal energy in Ireland?
Answer:
Almost 30%.

Question 16.
Which country of the world uses most amount of geo-thermal energy to generate electricity?
Answer:
The United States of America.

Question 17.
The use of which substance can be reduced by generating electricity by using geo-thermal energy?
Answer:
The use of fossil fuel can be reduced.

Question 18.
What is the average density of earth crust?
Answer:
Only 2.6 to 3.3 gram / cubic cm.

Question 19.
What is the average density of matter near the centre of the earth?
it Answer: Almost 11 gram / cubic cm.

Question 20.
What is the average density of earth in respect of artificial satellites?
Answer:
5.5 gram / cubic cm.

Question 21.
Which wave can not pass through liquid or semi liquid medium?
Answer:
S wave can not pass through liquid or semi liquid medium.

Question 22.
What is increased with the increasing of pressure on the matter?
Answer:
Density increases.

Question 23.
Which layer of earth is present just below the earth crust?
Answer:
Mantle is present just below the earth crust.

Question 24.
Who wrote the famous science fiction of earth?
Answer:
Jule Verne.

Question 25.
Where is the layer SIMA situated?
Answer:
SIMA situated beneath the ocean.

Question 26.
What does SIMA consist of ?
Answer:
The layer SIMA consists of Silicon (Si) and Magnesium (Mg).

Question 27.
What the SIMA made up of?
Answer:
It is made up of basalt like ignious rock.

Question 28.
Where is the layer SIAL situated?
Answer:
SIAL is situated above SIMA.

Question 29.
What is the uppermost layer of the eartherust?
Answer:
The uppermost layer of the earthcrust is Soil.

Question 30.
Which gas is present covering most of the part of earth crust?
Answer:
Oxygen.

Question 31.
What is the second element of earth crust?
Answer:
Silicon is the second element of earth crust.

Question 32.
Which line seperates the two different elements and density layers?
Answer:
Discontinuity line.

Question 33.
Which line presents in between SIAL and SIMA?
Answer:
conrad discontinuity.

Question 34.
What is the temperature of mantle?
Answer:
2000°-3000°C.

Question 35.
W ist are the tnain elements of mantle?
Answer:
Nickel Ctromium, Magnesium and Silicon.

Question 36.
What is the meaning of the word asthenosphere?
Answer:
weaker layer.

Question 37.
How thick is the core?
Answer:
The core is 3500 km. thick.

Question 38.
What is the average temperature of the core?
Answer:
Almost 5600°C.

Question 39.
What is the density of core?
Answer:
Almost 9.1 to 13.1 gram / cubic cm.

Question 40.
What is the depth of inner core?
Answer:
5100 km to almost 6370 km.

Question 41.
What is the depth of outer core?
Answer:
2900 km to almost 5100 km.

Question 42.
Which line present between the mantle and the core?
Answer:
Gutenberg discontinuity.

Short Questions & Answers : (2 marks for each question)

Question 1.
What is magma?
Answer:
Due to enormous pressure and temperature the substances of the earth’s interior remain liquid, being mixed with gas and vapour is called magma.

Question 2.
What is lava?
Answer:
When hot molten magma of the earth’s interior, comes out through the cracks and joints on the earth’s surface, it is called lava.

Question 3.
In what state the mattrers remain if the pressure and temperature both are excessive in the interior of the earth?
Answer:
If the temperature in the interior of the earth increases the matter melts into liquid and expands in volume. On the other hand with the increasing of the pressure the volume decreases.

Question 4.
What is Geo-thermal energy?
Answer:
Geo-thermal heat is one type of energy. The heat of the earth gradually transferred to the earth crust. This heat is ealled Geo-thermal energy.

Question 5.
What is density?
Answer:
Density is the measure of mass present in unit voiume of substance.

Question 6.
What is the Earth core?
Answer:
The innermost layer of the carth lies encircles the centre of the earth is known as the Earth core.

Question 7.
What is a NIFE?
Answer:
The layer of the mantle that made up of Nickel and Ferrum is known as NIFE.

Question 8.
How is the Earth core divided?
Answer:
The Earth core is divided into two parts (i) inner core and (ii) outer core.

Long Questions & Answers : (3 marks for each question)

Question 1.
What is Seismic waves?
Answer:
The scientists have collect information about the earth interior by watching the movement of the seismic wave. The seismic wave passes through different substances. Sometimes it is rapid sometimes it is slow. There are two types of waves. One is P and another is S. P wave can pass through either solid or liquid. But S wave can not pass through liquid or semi-liquid materials.

Question 2.
What do you know by the term ‘Inner core’?
Answer:
The layer of earth lies surrounding the centre of the earth is known as inner core; the depth of the layer is about 5100 km to 6370 km. This layer has the maximum amount of pressure, temperature and density. Due to very high pressure all the substances remain here in solid state.

Question 3.
What is the ‘Outer core’?
Answer:
The layer that encles the inner core is called the Outer core. The depth of the outer core is 2900 km to 5100 km. Pressure, temperature and density is comparatively lesser than inner core. It rotates around the axis of the earth in semi-liquid state. Being in a viscous state the ferrum in the layer develops an electro-magnetic field for very high velocity from which the magnetism of the earth is formed.

Question 4.
What is the ‘mantle’?
Answer:
Below the crust there is mantle. The temperature of the mantle is 2000,3009°C. Density is 3.4 to 5.6 gram / cube cm. The main elements of the layer are iron, silicon, chromium, nickel and magnesium.

WBBSE Class 8 Geography Question Answer West Bengal Board

WBBSE Class 8 Geography Book Solutions West Bengal Board in English Medium

• Chapter 1 Interior of the Earth
• Chapter 2 Unstable Earth
• Chapter 3 Rocks
• Chapter 4 Pressure Belts and Winds
• Chapter 5 Cloud and Rain
• Chapter 6 Climatic Regions
• Chapter 7 Human Activities and Environmental Degradation
• Chapter 8 Some Neighbouring Countries of India and Its Relationship with Them
• Chapter 9 North America
• Chapter 10 South America
• Chapter 11 Oceania

WBBSE Class 8 Geography Book Solutions West Bengal Board in Hindi Medium

• Chapter 1 पृथ्वी का आंतरिक भाग
• Chapter 2 परिवर्तनशील पृथ्वी
• Chapter 3 चट्टान
• Chapter 4 चापवलय और वायु प्रवाह
• Chapter 5 मेघ – वर्षा
• Chapter 6 जलवायु क्षेत्र
• Chapter 7 मनुष्य के कार्य-व्यापार एवं परिवेश का ह्रास
• Chapter 8 भारत के पड़ोसी देश और उनके साथ संबंध
• Chapter 9 उत्तरी अमेरिका
• Chapter 10 दक्षिणी अमेरिका
• Chapter 11 ओशोनिया

WBBSE Class 8 Solutions

Detailed explanations in West Bengal Board Class 10 Life Science Book Solutions Chapter 5D Biodiversity and Conservation offer valuable context and analysis.

WBBSE Class 10 Life Science Chapter 5D Question Answer – Biodiversity and Conservation

Short Snswer Type Questions : 2 Marks

Question 1.
What are the objectives of conservation.
Answer:
The objective behind conservation of living resources are as follows :

1. To maintain essential ecological processes and life supporting system.
2. To preserve the diversity of species or the range of genetic material found in the world’s organisms.
3. To ensure sustainable utilisation of species and ecosystems which support millions of rural communities as well as major industries.

Question 2.
How are forests useful for the protection of wall?
Answer:
Forests protect land by :

1. preventing soil erosion by wind and water and
2. by checking the velocity of wind or raindrops striking the ground and reducing dislodging of the soil particles.
3. The root systems firmly hold the soil.

Question 3.
State the role of forest in retaining sub-soil water.
Answer:
Role of forests in retaining sub-soil water :
(i) Forests add humus to soil which absorbs water during rains. It does not allow it to evaporate or run of quickly.

Question 4.
What steps are required for conservation of forest.
Answer:
Steps for conservation of forests :

1. Discourage the use of firewood, by providing alternative sources of energy like biogas etc.
2. Limit felling of trees for timber, combined with tree plantation.
3. Adopting modern forest management practices like optimization of silviculture, use of irrigation, fertilizers, bacterial and mycorrhizal inoculation, control of weeds, breeding of new varities and use of biotechnology.

Question 5.
Distinguish between the following :
Answer:

Question 6.
What is biodiversity?
Answer:
The variety of living organisms in an ecosystem is called biodiversity. The exact number of species in the world is not known. The taxonomists have described about 1.4 million species. But taxonomists estimate that there are 4 to 31 million more species. Much of these species are unnoticed.

Question 7.
What is MAB?
Answer:
Man and biosphere programme is an international biological programme of UNESCO (United Nations Educational Scientific and Cultural Organisation) which was started in 1971 but was introduced in India in 1986. MAB has studied human environment, impact of human interference and pollution on biotic and abotic environment and conservation strategies for the present as well as future.

Question 8.
What do you mean by hotspots of biodiversity?
Answer:
The concept of hotspots was developed by Norman Myers in 1988. These areas are rich in species diversity with high endemism and priority areas for in situ conservation because these areas are under constant threat. Endemism is the situation where particular species confined to a particular area and not found anywhere else. The key criteria for determining a hot spot are
(i) Number of endemic species.
(ii) Degree of threat which is measured in terms of habitat loss.

Question 9.
Name the hotspots present in the Indian territory?
Answer:
There are four hotspots in India.

1. East Himalaya : India’s Hotspot -1
2. Indo-Burma : India’s Hotspot -2
3. Western Ghats and Sri lanka : India’s Hotspot -3
4. Sundaland : India’s Hotspot -4

Question 10.
Write about the causes of destruction of biodiversity?
Answer:
Causes of destruction of biodiversity :
The biodiversity is threatened all over the world. Acid rain, pollution, urban development and agriculture are present everywhere. The expanding human populations destroy the habitat. It is the main threats to biological diversity.

Humans are exploiting about 40% net primary production on the earth. They convert the natural areas into agricultural land. They destroy the native species. The loss of habitat destroys thousands of native plants and animals.

Long Answer Type Questions : 5 Marks

Question 1.
How is the preservation of wildlife important for human progress?
Answer:

1. Economic value : Provide diverse variety of food materials.
2. In argiculature : Wildlife provides variations. Using these in breeding programmes man has been able to produce high yielding and disease resistant varieties of crop plants.
3. In animal husbandry and fishery : Breeding of high yielding disease and stres resistance breeds of animals and better quality fishes has been possible by introduction and hybridization.
4. In modern medicine and surgery : Selection and development of strains of anibiotic producing microoganisms. Identification of medicines and drug producing plants like Cinchona and Rauwolfia.
5. Development of biofertilizers : Use of Nostoc, Anabaena and Azospirllium has been possible as a result of study of naturally growing microorganisms.
6. Biological control of pests and pathogens: Cactoblatis cactorum used to control growth of cacti in Australia, has been possible through identification of wildly occuring insects.

Question 2.
What are the needs for conservation?
Answer:

1. Maintenance of balance of nature
2. Economic value
3. Scientific value
4. Aesthetic value – enjoyment of the beauty of nature
5. Culural value
6. Protection of our civilization
7. Evolutionary responsibility

Question 3.
What are the strategies for conservation of wildlife?
Answer:
i. Forest fires-natural and man-made

ii. Hunting as sport e.g. disappearance of Dodo a unique bird of Mauritius and Cheetah from India.

iii. Deforestation and habitat destruction: Due to the conversion of habitat of wildlife for human settlement, crop lands, grazing grounds, plantation, mining, dams reservoirs, harbours.

iv. Introduction of exotic species: Causes competition, predation, habitat destruction, transmission of diseases, e.g. introduction of goats and rabbits in the Islands of Pacific and Indian Ocean have destroyed habitats of plants, birds and reptiles.

v. Over-exploitation of natural resources: Killing of animals for hides and skin, meat and flesh, aphrodisiacs and decoration pieces. Collection of rare plants of wild origin for pharmaceuticals, perfumes, cosmetics and for museum collections. Students inadvertently destroy rare plants and insects during excursions for collections.

Question 4.
Write the importances of biodiversity?
Answer:
Importance of the following biodiversity :

1. Forests hold back flood waters and recycle CO₂ and nutrients.
2. Insects pollinate crops and control insect pests.
3. The subterranean organisms promote soil fertility through decomposition.
4. Many of these undescribed species will provide new food crops, petroleum substitutes, new fibres and pharmaceuticals. All of these functions require large healthy populations.
5. Large populalions promote the genetic diversity.

This diversity is required for the survival of the species in the changing environment. The genetic diversity is lost forever. The zoologists are trying to save endangered species. But they are able to save only a tiny portion of genetic pool.

Question 5.
What are the causes for the extinction of wildlife?
Answer:
Causes for the extinction of wildlife :
Natural calamities : Many species of wildlife have become depleted or extinct because of natural calamities, such as earthquakes, floods, droughts, fire and epidemics.
Depriving of natural habitat: A major cause of the extinction of wildlife is human activity. Conversion of vast areas of grasslands and forests into agricultural lands have deprived wildlife of their natural habitats.

Deforestation : Wherever civilization advances, forests are destroyed. Forests were cleared to obtain building material, fuel or land for agriculture.

Hunting : Hunting for sport or for animal products led to large scale endangerment and extinction of many species of animals. Tigers and leopards were killed for their skins, rhinoceros for their horns, elephants for their tusks, musk deer for the perfumed pods under their bellies, black bears for their gall bladder, alligators for their skin used in the making of fancy luggage and shoes and snakes for making belts and purses. Fantastic price are obtained in the underground markets.

Question 6.
Write about in situ conservation.
Answer:
In situ conservation : It is conservation and protection of the whole ecosystem and its biodiversity at all levels in order to protect the threatened species. Two alternate methods are being used to save biodiverstiy, hotspots and protected areas.
Hotspots : They are areas with high density of biodiversity or mega diversity which are also the most threatened ones. Ecologically hotspots are determined by four factors.

• Number of species/species diversity.
• Degree of endemism.
• Degree of threat to habitat due to its degradation and fragmentation.
• Degree of exploitation.

Myers (1988) initially identified 12 hotspots with 14% of plant species in an area of only 0.2%. Four more hotspots were added by Myers (1991). Today the number of hotspots identified by ecologists is 34 , covering an area less than 2% of land surface with about 20% of human population living there. India has three hotspots Indo-Burma, Himalayas and Western Ghats – Sri Lanka. India is even otherwise a country of mega diversity with 2.4% of land area and having 8.1% ‘of global diversity. Major centres of biodiversity are Agasthyamalai hills, Silent valley and Amambalam reserve. There is high degree of endemism as well as richness of species of flowering plants, amphibians, reptiles, some mammals and butterflies. Indo-Burma hotspot extends from Bhutan to Myanmar covering most of north-east. Valleys of this region are rich in endemic species, it has been an active centre of evolution of flowering plants, being rich in primitive angiosperm genera (e.g., Magnolia, Betula) and primitive angiosperm families (e.g., magnoliaceae, winteraceae).

Protected areas : They are ecological/biogeographical areas where biological diversity along with natural and cultural resources is protected, maintained and managed through legal or other effective measures. They are delimited on the basis of biological diversity, e.g. cold desert (Ladakh and Spiti), hot desert (Thar), wetland (Assam), saline swampy area (Sundarbans) etc. Protected areas include national parks, sanctuaries and biosphere reserves.

National parks: They are areas maintained by government and reserved for betterment of wildlife. Cultivation, grazing, forestry and habitat manipulation are not allowed.

Sanctuaries : They are tracts of land with or without lake where wild animals/ fauna can take refuge without being hunted. Other activities like collection of forest products, harvesting of timber, private ownership of land, tilling of land etc. are allowed. India has 448 wildlife sanctuaries.

Biosphere reserves : They are multipurpose protected areas which are meant for preserving genetic diversity in representative ecosystems of various natural biomes and unique biological communities by protecting wild populations, traditional life style of tribals and domesticated plant/animal genetic resources. Creation of biosphere reserve was initiated in 1975 under MAB programme of UNESCO. Till May 2002,408 biosphere reserves had been established in 94 countries. In India, 14 potential sites were identified in 1979 by Core Advisory Group. They are also notified as national parks. Each biosphere reserve has

Core or Natural Zone : No human activity is allowed. The area is undisturbed and has legally protected ecosystem.

Buffer Zone : It surrounds the core area. Limited human activity is allowed like resource use strategies, research and education.

Transition Zone (Manipulation Zone) : It is the outermost or peripheral part of biosphere reserve where an active cooperation is present between reserve management and local people for activities like settlements, cropping, recreation, forestry and other economic uses without disturbing ecology. Transition zone has different parts like forestry, agriculture, tourism and restoration regions. Restoration region is degraded area which is selected for restoration to near natural form.

Importance of biosphere reserves includes :

1. Restoration – Biosphere reserves help in restoration of degraded ecosystems and habitats.
2. Conservation – They are means of conserving genetic resources, species, ecosystems and landscapes without uprooting the local people.
3. Development – They ensure culturally, socially and ecologically sustainable economic development.
4. Monitoring – There is a regular monitoring of development and conservation progress.
5. Education and research – Each biosphere reserve supports education of information about research, restoration, conservation and development aspects at the national and global levels.

Sacred forests and lakes – Sacred forests (= sacred groves) are forest patches around places of worship which are held in high esteem by tribal communities. They are the most undisturbed forest patches (island of pristine forests), which are often surrounded by highly degraded landscapes. They are found in several parts of India, e.g.- Karnataka, Maharashtra, Rajasthan. Not a single branch is allowed to be cut from these forests. As a result many endemic species which are rare or have become extinct elsewhere can be seen to flourish here.

Question 7.
Write about ex situ conservation :
Answer:
Ex situ conservation : It is conservation of threatened plants/animals in places outside their natural homes. Ex situ conservation includes offsite collections and gene banks. The two are also a source of genetic material for breeders and genetic engineers.

Offsite collections : They are live collections of wild and domesticated species in botanical gardens, zoological parks, wildlife safari parks, arboreta (approx arboretums = arboretums) etc. Currently, there are more than 1500 botanical gardens and arboreta (gardens with trees and shrubs) having more than 80,000 species. Many of them have seed banks, tissue culture facilities and other in situ technologies.The number of zoos/ zoological parks is more than 800 . They have about 3000 species of mammals, birds, reptiles and amphibians. Most of them have well managed captive breeding programmes. As a result many animals which have become extinct in the wild continue to be maintained in zoological parks.

Gene banks : They are institutes that maintain stocks of viable seeds (seed banks), live growing plants (orchards), tissue culture and frozen germplasm with the whole range of genetic variability.

Seed banks : Seeds are of two types, orthodox and recalcitrant. Orthodox seeds are those seeds which can tolerate reduction in moisture content (upto 5%), anaerobic conditions and low temperature of -10° to -20°C or even lower for prolonged periods, e.g. cereals, legumes. At intervals the seeds are allowed to germinate, form plants and develop fresh seeds for storage. Recalcitrant seeds are those seeds which get killed on reduction of moisture and exposure to low temperature, e.g., tea, cocoa, jackfruit, coconut. They can be stored for shorter duration after treatment with fungicides in rooms having humid air and normal oxygen.

Orchards : Plants with recalcitrant seeds are grown in orchards where all possible strains and varieties are maintained, e.g. litchi, oil palm, rubber tree etc. .

Tissue culture – It is carried out through callus formation, embryoids, pollen grain culture and shoot tip culture for those plants which are either seedless, have recalcitrant seeds, variable seed progeny or where clone is to be maintained. The method is useful in maintaining a large number of genotypes in small area, rapid multiplication of even endangered species and for hybrid rescue. Shoot tip culture maintains virus free plants. It is used for international exchange of germplasm in vegetatively multiplied cultivars, e.g., banana, potato.

Cryopreservation : Preservation at -196°C (liquid nitrogen) can maintain tissue culture, embryos, animal cells/tissues, spermatozoa indefinitely. The cryopreserved material is revived through special technique when required.

Question 8.
Give a list of some important wild animal on india.
Answer:

Question 9.
List some National Parks of India
Answer:

Question 10.
Compare National park, sanctuary and biosphere reserve.
Answer:

National park	Sanctuary	Biosphere reserve
1. Hitched to the habitat for particular wild animal species like tiger, lion, angul, rhino etc.	Generally species-oriented as Citrus, pitcher plant, Great Indian Bustard.	Not hitched to anyone, two or more species, but to the whole ecosystem i.e. totality of all forms of life i.e., ecosystem oriented.
2. India, the size range is 0.04 to 3162 sq. km. Most common (in about 40%) is 100 to 500. km. In 15% is 500 to 1000sq. km.	Size range.is 0.61 to 7818 sq. km. Most common (in about 40%) is 100 to 500 sq. km. In 25% is 500 to 1000 sq. km.	Size range over 5670 sq. km.
3. Boundaries circumscribed by legislation.	Boundries not sacrosanct.	Boundaries circumscribed by legislation.
4. Except the buffer zone, no biotic interference.	Limited biotic interference.	Except of buffer zone, no biotic interference.
5. Tourism permissible.	Tourism permissible.	Tourism normally not permissible
6. Research and scientific management lacking	Lacking	Managed
7. So far no attention to genepools and conservation.	So far no attention.	Attention given

Question 11.
Give a list of some important sanctuaries in India.
Answer:

Name, location and area (in sq. km.)	Important animals found
1. Annamalai Sanctuary, Coimbatore (Tamil Nadu), 958	Elephant, tiger, panther, gaur, sambhar, spotted deer, sloth bear, wild dog, barking deer.
2. Jaldapara Sanctuary, Madarihat (West Bengal), 1,155	Rhino, elephant, tiger, leopard, gaur, deer, sambhar, different kinds of birds.
3. Keoladeo Ghana Bird Sanctuary, Bharatpur (Rajastnan) (Earlier it was once the duck shooting ground of a king), 29	Siberian crane, storks, egrets, herons, spoon bill etc. Drier parts of this marshy sanctuary have spotted deer, black buck, sambhar, wild boar, blue bull, python. This sanctuary is famous for aquatic birds.
4. Sultanpur Lake Bird Sanctuary, Gurgaon (Haryana), 12	Crane, sarus, spotbill, duck, drake, green pigeon, wild boar, crocodile, python.
5. Bir Moti Bagh Wildlife Sanctuary, Patiala (Punjab), 8.3 Mandi (Himachal Pradesh), 213	Nilgai, wild boar, hog deer, black buck, blue bull, jackal, peafowl, partridge, sparrow, myna, pigeon, dove.
6. Shikari Devi Sanctuary,	Black bear, snow leopard, flying fox, barking deer, musk deer, chakor, partridge.
7. Dachigam Sanctuary Srinagar, (Jammu and Kashmir), 89	Hangul or Kashmiri stag, musk deer, snow leopard, black bear, brown bear.
8. Mudumalai 11. wildlife Sanctuary Nilgiri (Tamil Nadu), 520	Elephant, gaur, sambhar, chital, barking deer, mouse deer, four homed antelope, langur, giant squirrel, flying squirrel, wild dog, wild cat, civet, sloth bear, porcupine, python, rat, snake, monitor lizard, flying lizard.
9. Nagarjuna Sagar Sanctuary Guntur, Kamool and Nalgonda (Andhra Pradesh), 3, 568 km	Tiger, panther, wild boar, chital, nilgai, sambhar, black buck, fox, jackal, wolf, crocodile.
10. Periyar Sanctuary, Idduki (Kerala), 777 km	Elephants, gaur, leopard, sloth bear, sambhar, bison, black · langur, hornbill, egret. It is famous for elephants.
11. Chilka Lake Bird Sanctuary, Balagaon (Odisha) (Largest brackish water lagoon in Asia), 900 km	An oasis of birds like water fowls ducks, crane’s, golden plovers, sand pipers, flamingoes.
12. Manas Wildlife Sanctuary, Kamrup (Assam)	Tiger, panther, rhino, gaur, wild buffalo, sambhar, swamp deer, golden Tangur, wild dog, wild boar.

Question 12.
Make a list of some Biosphere reserves in India.
Answer:

Biosphere Reserve	State
1. Nilgiri (First biosphere reserve established in India (1986)]	Karrnnataka
2. Nanda Devi(1988)	Uttaranchal
3. Gulf of Mannar	Tamil Nadu
4. Agasthyamalai	Kerela.
5. Sundarbans	West Bengal
6. Panchmari	M.P
7. Manas	Assam
8. Kanchenjunga	Sikkim
9. Nokrek (Tura range)	Meghalaya
10. Great Nicobar	Andaman and Nicobar
11. Similipal	Odisha
12. Dibru Saikhowa	Assam
13. Dehang Debang	Arunachal Pradesh
14. Achanakmar – Amarkantak	Chhattisgarh

Question 13.
State the environmental problems of Sundarban.
Answer:
The threats to the mangrove eco-system are arising partly due to biotic pressure from the surrounding environment and partly due to human induced or natural changes in the upper catchments. These can be outlined as below

• Reduced flow of sweet water into Sundarban mangrove system
• Extension of non-forestry land use into mangrove forest
• Straying of tiger into villages along the western boundary of Sundarban
• Demand for small timber and fuel wood for local consumption
• Poaching of tiger, spotted deer, wild boar, marine turtles, horse shoe crab etc
• Uncontrolled collection of prawn seedlings
• Uncontrolled fishing in the water of reserve forests
• Continuous trampling of river/creek banks by fishermen and prawn seed collectors
• Chemical pollution through marine paints and hydrocarbons
• Long international border along the Eastern boundary of Indian Sundarban
• Organizational and infrastructure deficiencies

Question 14.
What do you mean by JFM?
Answer:
Joint Forest Management often abbreviated as JFM is the official and popular term in India for partnerships in forest movement involving both the state-forest departments and local communities. The policies and objectives of Joint Forest Movement are detailed in the Indian comprehensive National Forest Policy of 1988 and the Joint Forest Movement Guidelines of 1990 of the Government of India.

Although schemes vary from state to state and are known by different names in different Indian languages. Usually a village committee known as the Forest Protection Committee (FPC) and the Forest Department enter into a JFM agreement. Villagers agree to assist in the safeguarding of forest resources through protection from fire, grazing, and illegal harvesting in exchange for which they receive non-timber forest products and a share of the revenue from the sale of timber products.

Question 15.
What do you mean by PBR?
Answer:
People’s Biodiversity Register (PBR) : One of the mandates of the biodiversity board is to prepare biodiversity registers for each LSG involving the local communities. Biodiversity registers are being prepared with the help of the local people and hence referred as People’s Biodiversity Register (PBR).
Preparation of biodiversity register is an attempt to realize the biodiversity at

local self government level, states and the whole country. Identification of biological resources and documentation is one of the prerequisites for the Register preparation which can lead to new discoveries and development of new commercial products, patenting of such products, equitable distribution of benefits, if any, and through this paving the way for a new economic order in the country through biodiversity conservation.

PBR is not simply a register with names of species and their distribution in a given area. It is a comprehensive data base recording people’s traditional knowledge and insight of the status, uses, history, ongoing changes and forces driving these changes on the biological diversity resources of their own localities. This will also provide information on the current utilization patterns of biodiversity, its economic benefits to the local communities. The registers form a baseline data for future management strategies required for the sustainable utilization of biodiversity in a decentralized manner. Further, it helps equitable sharing of benefits arising out of commercial utilization of biodiversity resources and knowledge on their uses. The biodiversity register offers conservation, protection of IPR and the traditional knowledge.

Multiple Choice Questions : 1 Mark

Question 1.
Rare endangered and endemic taxa can be found intact and flourishing in
(a) sacred groves
(b) tropical forest
(c) oases
(d) buffer zone of biosphere reserve.
Answer:
(a) sacred groves

Question 2.
Antilope cervicapra/Black Buck is
(a) vulnerable
(b) endangered
(c) critically endangered
(d) extinct in the wild.
Answer:
(a) vulnerable

Question 3.
Susceptibility to extinction is due to
(a) large body size
(b) small population
(c) high trophic level
(d) all of these
Answer:
(d) all of these

Question 4.
World Conservation Union maintains
(a) red data book
(b) red list
(c) pink list
(d) both (a) and (b)
Answer:
(d) both (a) and (b)

Question 5.
Keoladeo Ghana National Park is situated in
(a) Bihar
(b) Rajasthan
(c) Uttar Pradesh
(d) West Bengal
Answer:
(b) Rajasthan

Question 6.
First biosphere reserve was established in 1986 at
(a) Nilgiri
(b) Nanda Devi
(c) Rann of Kutch
(d) Sundarbans
Answer:
(a) Nilgiri

Question 7.
Nanda Devi Biosphere Reserve is found in
(a) Uttaranchal
(b) Assam
(c) Himachal Pardesh
(d) Andhra Pardesh.
Answer:
(a) Uttaranchal

Question 8.
Symbol of WWF is
(a) Tiger
(b) Rhododendron
(c) White bear
(d) Giant panda.
Answer:
(d) Giant panda.

Question 9.
National Forest Policy was enunciated in
(a) 1972
(b) 1978
(c) 1982
(d) 1988
Answer:
(d) 1988

Question 10.
Social Forestry Programme was started in
(a) 1970
(b) 1976
(c) 1968
(d) 1985
Answer:
(b) 1976

Question 11.
Forest destruction results in
(a) loss of wild life
(b) floods and drought
(c) soil erosion
(d) all of these
Answer:
(d) all of these

Question 12.
Tiger is not a resident in which one of the following National park?
(a) Sundarbans
(b) Gir
(c) Jim Corbett
(d) Ranthambhor
Answer:
(b) Gir

Question 13.
Chipko movement was launched for the protection of
(a) forests
(b) livestock
(c) wetlands
(d) grasslands
Answer:
(a) forests

Question 14.
Which one of the following is a pair of endangered species?
(a) Garden lizard and Mexican poppy
(b) rhesus monkey and sal tree
(c) Indian peacock and carrot grass
(d) hornbill and Indian aconite
Answer:
(d) hornbill and Indian aconite

Question 15.
If the Bengal tiger becomes extinct
(a) hyenas and wolves will become scarce
(b) the wild areas will be safe for man and domestic animals
(c) its gene pool will be lost for ever
(d) the populations of beautiful animals like deers will get stabilized.
Answer:
(d) the populations of beautiful animals like deers will get stabilized.

Question 16.
One of the ex situ conservation methods for endangered species is
(a) wildlife sanctuaries
(b) biosphere reserves
(c) cryopreservation
(d) national parks
Answer:
(c) cryopreservation

Question 17.
Biosphere reserves differ from national parks and wildlife sanctuaries because in the former
(a) human beings are not allowed to enter
(b) people are an integral part of the system
(c) plants are paid greater attention than the animals
(d) living organisms are brought from all over the world and preserved for posterity
Answer:
(b) people are an integral part of the system

Question 18.
Red Data Book is concerned with
(a) red pigmentation of plants
(b) red algae
(c) endangered species
(d) exotic species
Answer:
(c) endangered species

Question 19.
The chipko movement for conservation of forests was started in 1972 in
(a) North Kanara district
(b) Silent Valley
(c) Sundarbans
(d) Tehri-Garhwal
Answer:
(d) Tehri-Garhwal

Question 20.
Which of the following plant is an endangered species in India?
(a) Lycopodium sp.
(b) Pinus roxburghii
(c) Hydrua
(d) Cedrus deodara.
Answer:
(a) Lycopodium sp.

Question 21.
Under the umbrella of social forestry a system has been launched in which agriculture and forestry are involved. Select the name of the system
(a) block cutting system
(b) jhum cultivation system
(c) taungya system
(d) none of these
Answer:
(c) taungya system

Question 22.
Which of the following birds is on the verge of extinction in India?
(a) Peacock
(b) Pintail ducks
(c) Hornbill
(d) Great Indian Bustard
Answer:
(d) Great Indian Bustard

Question 23.
Germplasm conservation at liquid N₂ temperature is
(a) stratification
(b) cryopreservation
(c) scarification
(d) none of these
Answer:
(b) cryopreservation

Question 24.
Which one of the following the first national park in India?
(a) Kanha national park
(b) Periyar national park
(c) Corbett national park
(d) Bandipur national park
Answer:
(a) Kanha national park

Question 25.
Deforestation causes
(a) water pollution
(b) soil erosion
(c) noise pollution
(d) soil pollution
Answer:
(b) soil erosion

Question 26.
Which national park is the new home of the Indian one-horned rhinoceros ?
(a) Dudhwa
(b) Corbett
(c) Kanha
(d) Bandhavgarh
Answer:
(a) Dudhwa

Question 27.
Which was the first national park established in India?
(a) Kanha
(b) Jim corbett
(c) Kaziranga
(d) Gir
Answer:
(a) Kanha

Question 28.
List of endangered species was released by
(a) IUCN
(b) BBC
(c) WCC
(d) UN
Answer:
(a) IUCN

Question 29.
A threatened species category included
(a) only endangered species
(b) only vulnerable species
(c) endangered and rare species
(d) endangered, vulnerable and rare species
Answer:
(d) endangered, vulnerable and rare species

Question 30.
and are combination of Agroforestry
(a) Fodder crops, fibre crop
(b) Food crops, fibre crop
(c) Trees, grasses
(d) Food crops, tree crop
Answer:
(d) Food crops, tree crop

Question 31.
A non-renewal source of energy is
(a) Wild life
(b) Fossil fuels
(c) Water
(d) Forest
Answer:
(b) Fossil fuels

Question 32.
A plant endemic to India is
(a) Banyan
(b) Ginkgo
(c) Sequoia
(d) Triticum
Answer:
(a) Banyan

Question 33.
A recent technique for the study of vegetation is
(a) Ground photography
(b) Remote sensing
(c) Field work
(d) Observation
Answer:
(b) Remote sensing

Question 34.
A renewable exhaustible natural resource is
(a) Forest
(b) Coal
(c) Petroleum
(d) Minerals
Answer:
(a) Forest

Question 35.
A species restricted to a given area is
(a) Endemic species
(b) Allopatric species
(c) Sympatric species
(d) Sibling species
Answer:
(a) Endemic species

Question 36.
According to IUCN red list, what is the status of Red Panda (Ailurus fulgens)
(a) Critically endangered
(b) Endangered species
(c) Vulnerable species
(d) Extinct species
Answer:
(b) Endangered species

Question 37.
Agroforestry and social forestry both include
(a) Production forestry
(b) Commercial forestry
(c) Afforestation
(d) Plantation of trees
Answer:
(d) Plantation of trees

Question 38.
An endangered bird is
(a) Passenger Pigeon
(b) Pink-headed duck
(c) Great Indian Bustard
(d) Vulture
Answer:
(c) Great Indian Bustard

Question 39.
An endangered species from the following
(a) Azardirachta
(b) Rosa indica
(c) Rauvolfia serpentina
(d) Acacia arabica
Answer:
(c) Rauvolfia serpentina

Question 40.
An example of ex-situ conservation is
(a) Seed bank
(b) Sacred groves
(c) National parks
(d) Wildlife sanctuary
Answer:
(a) Seed bank

Question 41.
An exhaustible renewable resource is
(a) Coal
(b) Solar energy
(c) Fresh water
(d) Petroleum
Answer:
(c) Fresh water

Question 42.
An inexhaustible and renewable source of energy is
(a) Wood
(b) Natural gas
(c) Fossil fuel
(d) Hydropower
Answer:
(d) Hydropower

Question 43.
Antíropogenic extinction occurs due to
(a) Earthquakes
(b) Floods
(c) Changing environmental conditions
(d) Human activities
Answer:
(d) Human activities

Question 44.
Biogas is which type of natural resources
(a) Renewable
(b) Inexhaustible
(c) Non-conventional
(d) Both(a) and(c)
Answer:
(a) Renewable

Question 45.
Chipko Movement is an example of forest conservation through
(a) Tehri-Garhwal district
(b) Uttaranchal
(c) Public awareness and participation
(d) Political issue
Answer:
(c) Public awareness and participation

Question 46.
Chipko movement is related to
(a) Forest conservation
(b) Soil conservation
(c) Water conservation
(d) Wetland conservation
Answer:
(a) Forest conservation

Question 47.
Chipko movement was launched for protection of
(a) Forests
(b) Grasslands
(c) Wetlands
(d) Livestocks
Answer:
(a) Forests

Question 48.
Conservation of species in its natural habitat is
(a) In-situ
(b) Ex-situ
(c) In-vitro
(d) Both(b) and(c)
Answer:
(a) In-situ

Question 49.
Deforestation brings about
(a) Soil erosion
(b) Weed control
(c) Decreased drought
(d) Increased sunlight
Answer:
(a) Soil erosion

Question 50.
Deforestation is caused due to
(a) Silviculture
(b) Construction of roads
(c) Rainfall
(d) Plantation of trees
Answer:
(b) Construction of roads

Question 51.
Deforestation is the major causal agent of
(a) Depletion of natural resources
(b) Environmental pollution
(c) Desertification of habitat
(d) Genetic erosion
Answer:
(c) Desertification of habitat

Question 52.
Deforestation will decrease
(a) Soil erosion
(b) Land slides
(c) Soil fertility
(d) Rainfall
Answer:
(d) Rainfall

Question 53.
Development of botanical garden is what type of conservation
(a) Ex-situ
(b) A common
(c) An easy
(d) In-situ
Answer:
(a) Ex-situ

Question 54.
Ex-situ conservation is carried out in
(a) Sanctuary
(b) National park
(c) Biosphere reserve
(d) Zoo
Answer:
(d) Zoo

Question 55.
Extensive planting of trees to increase forest cover is called
(a) Deforestation
(b) Agroforestry
(c) Social forestry
(d) Afforestation
Answer:
(d) Afforestation

Question 56.
For mapping, Remote sensing equipment is mounted on
(a) Aircraft and satellite
(b) Ship and spacecraft
(c) Satellite and spacecraft
(d) All of these
Answer:
(a) Aircraft and satellite

Question 57.
Forests control drought by
(a) Preventing soil erosion
(b) Increasing oxygen
(c) Increasing humidity and rainfall
(d) Preventing floods
Answer:
(c) Increasing humidity and rainfall

Question 58.
Fresh water present on earth is
(a) 97.5%
(b) 0.01%
(c) 2.5%
(d) 1.97%
Answer:
(c) 2.5%

Question 59.
Fresh water problem arises due to
(a) Globally available stocks are insufficient
(b) Uneven distribution on earth
(c) No regeneration of required quantity through natural hydrological cycle
(d) Anyone of the above
Answer:
(d) Anyone of the above

Question 60.
Gamma and X-rays are not used for remote sensing because
(a) They are absorbed by object
(b) They are reflected by object
(c) They are absorbed by layer of atmosphere
(d) They are not absorbed
Answer:
(c) They are absorbed by layer of atmosphere

Question 61.
Geo-stationary satellites
(a) Rotate very fast
(b) Are located near the earth
(c) Are stationary
(d) Rotate with speed equal to that of earth
Answer:
(d) Rotate with speed equal to that of earth

Question 62.
Human dominated biosphere is called
(a) Troposphere
(b) Stratosphere
(c) Hemisphere
(d) Noosphere
Answer:
(d) Noosphere

Question 63.
In a National Park protection is provided to
(a) Entire ecosystem
(b) Flora and fauna
(c) Fauna only
(d) Flora only
Answer:
(b) Flora and fauna

Question 64.
In India, common type of forest is
(a) Tropical thorn forests
(b) Sal and Teak forests
(c) Tropical moist deciduous forest
(d) Tropical dry deciduous forest
Answer:
(d) Tropical dry deciduous forest

Question 65.
Inexhaustible resource among the following is
(a) Minerals
(b) Solar energy
(c) Plants
(d) Fossil fuels
Answer:
(b) Solar energy

Question 66.
INSAT system is type of
(a) Satellite
(b) Geo-stationary satellite
(c) Sun-synchronous satellite
(d) Orbital satellite
Answer:
(b) Geo-stationary satellite

Question 67.
Islands have higher number of endemic species as they are separated from land masses by
(a) Deserts
(b) Mountains
(c) Large expanses of water
(d) Valleys
Answer:
(c) Large expanses of water

Question 68.
It is not a protected forest
(a) Reserve forest
(b) Sanctuary
(c) Core of biosphere
(d) Orchard
Answer:
(d) Orchard

Question 69.
IUCN stands for
(a) Indian Union of chemical Nomenclature
(b) Indian Union of Conservation of Nature
(c) International Union for Conservation of Nature
(d) International Union for Conservation of Nutrients
Answer:
(c) International Union for Conservation of Nature

Question 70.
Life supporting zone of earth’s surface is
(a) Lithosphere
(b) Biosphere
(c) Stratospere
(d) Ecotene
Answer:
(b) Biosphere

Question 71.
Main cause of extinction of species from tropical areas is
(a) Afforestation
(b) Deforestation
(c) Pollution
(d) Soil erosion
Answer:
(b) Deforestation

Question 72.
Main source of water to soil is
(a) Rainfall
(b) River
(c) Canals
(d) Lakes
Answer:
(a) Rainfall

Question 73.
Maximum use of fresh water is in
(a) Agriculture
(b) Domestic use
(c) Industry
(d) Pisciculture
Answer:
(a) Agriculture

Question 74.
More than 70% of world’s fresh water is contained in
(a) Ponds
(b) Glaciers and polar ice caps
(c) Green land
(d) Oceans
Answer:
(b) Glaciers and polar ice caps

Question 75.
Most effective controlling flood is
(a) Deforstation
(b) Constructing dams
(c) Reforestation
(d) Dagging canal
Answer:
(c) Reforestation

Question 76.
Most of the endangered species are victims of
(a) Acid rain
(b) Competition with exotic species
(c) Over hunting
(d) Habitat Destruction
Answer:
(d) Habitat Destruction

Question 77.
Natural resource which have definite cycle is
(a) Exhaustible Non-renewable
(b) Inexhaustible
(c) Non conventional
(d) Exhaustible Renewable
Answer:
(d) Exhaustible Renewable

Question 78.
Natures hydrogical cycle involves
(a) Evaporation, condensation
(c) Evaporation, precipitation
(b) Condensation, precipitation
(d) Evaporation, condensation and precipitation
Answer:
(d) Evaporation, condensation and precipitation

Question 79.
Out of total amount of water, the water found in seas and oceans is about
(a) 70%
(b) 90%
(c) 97%
(d) 85%
Answer:
(c) 97%

Question 80.
Planned management of natural resources is
(a) Not possible
(b) Not easy
(c) called conservation
(d) Called depletion
Answer:
(c) called conservation

Question 81.
Plantation of trees along with monocot crops is known
(a) Agroforestry
(b) Silviculture
(c) Social forestry
(d) Afforestation
Answer:
(a) Agroforestry

Question 82.
Planting of trees on unused farm land, rail and road sides etc. is called
(a) Commercial forestry
(b) Agroforestry
(c) Social forestry
(d) Reforestation
Answer:
(a) Commercial forestry

Question 83.
Planting of trees, shrub sand others in between crop plants for commercial exploitation and stabilization of soil is
(a) Taungya system
(b) Social forestry
(c) Agroforestry
(d) Production plantation
Answer:
(c) Agroforestry

Question 84.
Plants of endangered species are conserved through
(a) Herbarium
(b) Gene library
(c) Gene bank
(d) Reducting pollution
Answer:
(c) Gene bank

Question 85.
Population of species decreasing over a period called as
(a) Extinct
(b) Eliminated
(c) Endangered
(d) Rare
Answer:
(c) Endangered

Question 86.
Radiations not useful in remote sensing are
(a) UV radiations
(b) Microwave
(c) Ultrasonic waves
(d) Infra-red radiations
Answer:
(c) Ultrasonic waves

Question 87.
Red Data Book contains information about
(a) Red coloured insects
(b) Red eyed bird
(c) Red coloured fishes
(d) Endangered plants and animals
Answer:
(d) Endangered plants and animals

Question 88.
Red Data Book deals with
(a) Maintains and publish list of endangered and endemic species
(b) Maintains and publish list of Plants that are extinct
(c) Maintains and publish list off Animals that are extinct
(d) Maintains and publish list of dangerous species
Answer:
(a) Maintains and publish list of endangered and endemic species

Question 89.
Reforestation is
(a) Plantation of forests
(b) Plantation forests in deforested areas
(c) Cutting down of forests
(d) Management of forests
Answer:
(b) Plantation forests in deforested areas

Question 90.
Remote sensing involves the use of
(a) EMR
(b) NMR
(c) ESR
(d) SSR
Answer:
(a) EMR

Question 91.
Resources which are available in unlimited quantity are
(a) National resources
(b) Exhaustible resources
(c) Inexhaustible resources
(d) Natural resources.
Answer:
(c) Inexhaustible resources

Question 92.
Serious threat to wild life is
(a) Habitat destruction
(b) International trade
(c) Introduction of exotic species
(d) Over-exploitation
Answer:
(a) Habitat destruction

Question 93.
Shifting cultivation is also known as
(a) Taungya system
(b) Shum cultivation
(c) Social forestry
(d) Plant cultivation
Answer:
(b) Shum cultivation

Question 94.
Solar energy is which type of natural resources
(a) Renewable
(b) Non-renewable
(c) Exhaustible
(d) Inexhaustible
Answer:
(d) Inexhaustible

Question 95.
Taungya is practice of
(a) Shifting cultivation
(b) Agroforestry
(c) Production forestry
(d) Both A and B
Answer:
(d) Both A and B

Question 96.
The base on which remote sensors are mounted is termed as
(a) Camera
(b) Energy source
(c) Platform
(d) Scanner
Answer:
(c) Platform

Question 97.
The endangered fauna is
(a) The Great Indian Bustard
(b) Viviparous toad
(c) Forest owl
(d) Kashmiri stag
Answer:
(a) The Great Indian Bustard

Question 98.
The function of tree plantation is celebrated through
(a) Environment day
(b) Vanikaran
(c) Social forestry programme
(d) Vasant Mahotsav
Answer:
(c) Social forestry programme

Question 99.
The human activities resulting in endangered species are
(a) Poaching
(b) Deforestation
(c) Forest fires
(d) All of these
Answer:
(d) All of these

Question 100.
The life supporting gases such as O₂, CO₂ and N₂ are primarily concentrated in
(a) troposphere
(b) exosphere
(c) homosphere
(d) stratosphere
Answer:
(a) troposphere

Question 101.
The main reserve of fresh water on earth surface is
(a) Ground water
(b) Rivers
(c) Lakes
(d) Polar ice caps and glaciers
Answer:
(d) Polar ice caps and glaciers

Question 102.
The management of resources on earth which maintains the balance between human requirements and other species is
(a) Conservation
(b) Industrialization
(c) Diversity of ecosystem
(d) Geological diversity
Answer:
(a) Conservation

Question 103.
The natural cause for extinction of species is
(a) Floods
(b) Hunting
(c) Industrialization
(d) Destruction of natural habitats
Answer:
(a) Floods

Question 104.
The natural resources available in limited quantity at global level is
(a) Non-renewable
(b) Renewable
(c) Exhaustible
(d) Inexhaustible
Answer:
(c) Exhaustible

Question 105.
The natural resources which are continuously consumed by man but are replenished by nature with a reasonable period of time is called
(a) Exhaustible
(b) Inexhaustible
(c) Exhaustible renewable
(d) Exhaustible non-renewable
Answer:
(c) Exhaustible renewable

Question 106.
The percentage of evaporation of water from land and ocean surface are respectively
(a) 16 and 84%
(b) 84 and 16%
(c) 65 and 35%
(d) 60 and 40%
Answer:
(a) 16 and 84%

Question 107.
The restricted distribution of species in small area called
(a) Biome
(b) Niche
(c) Endemism
(d) Ectosphere
Answer:
(c) Endemism

Question 108.
The vehicle used to carry the sensor in remote sensing is
(a) Camera
(b) Shuttle
(c) Scanner
(d) Platform
Answer:
(d) Platform

Question 109.
There is decrease in because of deforestation
(a) Soil erosion
(b) Global warming
(c) Rainfall
(d) Drought
Answer:
(c) Rainfall

Question 110.
Which has caused maximum damage to Indian forests
(a) Selective harvesting
(b) Block cutting
(c) Taungya cultivation
(d) Jhum cultivation
Answer:
(d) Jhum cultivation

Question 111.
Which of the following acts as a main source of ground water?
(a) Rain
(b) River
(c) Ocean
(d) Canals
Answer:
(a) Rain

Question 112.
Which of the following soil is the best for plant growth?
(a) Loamy soil
(b) Clay
(c) Gravel
(d) Sandy soil
Answer:
(a) Loamy soil

Question 113.
Which of the following species is endemic?
(a) Vanda
(b) Drosera sp
(c) Gnetum ula
(d) Ginkgo biloba
Answer:
(d) Ginkgo biloba

Question 114.
Which one is not an exhaustible resource
(a) Solar energy
(b) Coal
(c) Rainfall
(d) Wind power
Answer:
(b) Coal

Question 115.
Which one is not endangered species?
(a) Bald Eagle
(b) Giant Panda
(c) Podophyllum
(d) Mergosa
Answer:
(d) Mergosa

Question 116.
Which one of the following in endangered species?
(a) Cuscuta
(b) Nepenthes
(c) Datura
(d) Butea sps.
Answer:
(b) Nepenthes

Question 117.
The recent technique used for study of vegetation is
(a) Remote sensing
(b) Field works
(c) Ground photography
(d) Observation
Answer:
(a) Remote sensing

Very Short Answer Type Questions : 1 Mark

Question 1.
What is the total number of Hotspot situated in the world?
Answer:
34.

Question 2.
Who many hotspots present in India.
Answer:
4

Question 3.
Write the two causes of loss of biodiverity.
Answer:
(i) Hunting and poaching. (ii) Land use pattern.

Question 4.
Name two natural calamities due to loss of biodiversity.
Answer:
(i) Earthquakes, (ii) Tsunami.

Question 5.
Name two exotic species causing loss of biodiversity.
Answer:
Parthenium (Plant) Pesiplaneta americana.

Question 6.
Name two mangrove forests in India.
Answer:
(i) Sundarban mangrove forest.
(ii) Andaman mangrove forest.

Question 7.
How many types of conservation there are?
Answer:
Two types- (i) In-situ conservation, (ii) Ex-situ conservation.

Question 8.
Name one National Park in West Bengal.
Answer:
Jaldapara National Park.

Question 9.
Name one Sanctuary in West Bengal.
Answer:
Chapramari Sanctuary.

Question 10.
Name one Reserve forest in West Bengal.
Answer:
Bauxa Reserve forest.

Question 11.
Name one Biosphere reserve in West Bengal.
Answer:
Sundarban Biosphere reserve

Question 12.
Give two examples of ex-situ conservation.
Answer:
Zoological garden, Botanical garden.

Question 13.
What is the temperature for cryopreservation.
Answer:
-196° C

Question 14.
What is the full form of JFM
Answer:
Joint Forest Management.

Question 15.
Where and when JFM was started in India?
Answer:
Arabari forest in West Midnapur in 1971.

Question 16.
What is PBR?
Answer:
People’s Biodiversity Register.

Question 17.
Name one Tiger Project in West Bengal.
Answer:
Sundarban Tiger Project.

Question 18.
Name one Rhino Project in West Bengal.
Answer:
Jaldapara Sanctuary One-horned Rhinoceros Reserve Project.

Question 19.
Name one Lion Reserve Project.
Answer:
Lion Reserve Project in Gir Forest.

Question 20.
Name the Crocodile Reserve Project in West Bengal.
Answer:
Bhagabatpur Crocodile Reserve Project.

Question 21.
Name one Red Panda Reserve Project in West Bengal.
Answer:
Singalila National Project : Red Panda Reserve Project; Darjeeling.’

Question 22.
Which Logo is used for Red Panda conservation.
Answer:
WWF-N.

Fill in the blanks with suitable words :

1. The species of plants and animals which have disappeared from the face of the earth are said to be ___________.
2. Gene for resistance against a pest on rice, brown plant hopper (Nilaparvata lugens) was identified from old varieties of rice from ___________.
3. About ___________ plant species and ___________ vertebrate species are threatened with extinction.
4. Species of plants and animals which are in danger of becoming extinct or have become rare and are at risk are known as ___________ species.
5. Species of plants and animals which have been reduced to a critical level and are in immediate danger of becoming extinct are known as ___________ species.
6. Species of plants and animals which have been severely depleted and are likely to move into endangered category are known as ___________ species.
7. Species of plants and animals which occur in small populations restricted to localised areas or are thinly scattered over more extensive range are known as ___________ species.
8. Conservation is concerned with plants, animals, micro-organisms and their ___________.
9. The rice pest that threatened the entire rice cultivation is ___________ ___________ (Scientific name)
10. Over-fishing is depleting the ___________ living resources.
11. In the ___________ zone of biosphere reserves, no human activity is permitted.
12. In ___________ zone of bíosphere reserves, large number of human activities are allowed.
13. Only ___________ Indian Bustard birds are still living.
14. There are ___________ National Parks in our country.
15. ___________ Forestry Programme aims at planting trees for aesthetic purposes in urban settlements.
Answer:
1. extinct
2. Kerala
3. 25,000 ; 1,000
4. threatened
5. endangered
6. vulnerable
7. rare
8. environment
9. Nilaparvata lugens
10. marine
11. core
12. manipulation
13. 800
14. 66
15. Urban.

State whether the following statements are True or False. If False, then write the correct statement

Question 1.
California condor, the largest flying birds, is being affected by human cleanliness.
Answer:
True.

Question 2.
Forests play an important role in reducing atmospheric pollution.
Answer:
True.

Question 3.
Agroforestry Programme aims at reviving forests on barren agricultural land.
Answer:
False. Agroforestry Programme aims at reviving ancient practice of using same land for farming, forestry and animal husbandry.

Question 4.
The Great Indian Bustard, inhabitant of semiarid areas of Rajasthan, Gujarat and Maharashtra is considered as a rare bird.
Answer:
False. The Great Indian Bustard, inhabtant of semi-arid areas of Rajasthan, Gujarat and Maharashtra is a highly endangered bird.

Question 5.
In manipulation zone of biosphere reserve, limited human activity is allowed.
Answer:
False. In buffer zone of biosphere reserve limited human activity is allowed.

Question 6.
In a sanctuary, protection is given only to animals.
Answer:
True.

Question 7.
In-situ protection refers to the conservation of wildlife in zoos and botanical gardens.
Answer:
False. In-situ protection refers to the conservation of wildlife in their natural habited.

Question 8.
Uttarakhand Biosphere Reserve includes Silent valley in north western Himalayas.
Answer:
False. Uttarakhand Biosphere Reserve includes Valley of Flowers in northwestern Himalayas.

Question 9.
Silent valley is located in Tamil Nadu.
Answer:
False. Silent Valley is located in Kerala.

Question 10.
Tropical rain forests are the most productive forest types in the world.
Answer:
True.

Detailed explanations in West Bengal Board Class 10 Life Science Book Solutions Chapter 5C Environment and Human Population offer valuable context and analysis.

WBBSE Class 10 Life Science Chapter 5C Question Answer – Environment and Human Population

Short Answer Type Questions : 2 Marks

Question 1.
What environmental damage are caused by mercury poliution? What are the main sources of mercury pollution?
Answer:
Mercury is a metal that when present in the water of rivers, lakes and seas contaminates fish, crustaceans, molluscs and other living organisms. The mercury accumulates along the food chain and, in each following trophic level, the amount of the metal within the individuals is higher. When humans eat contaminated animals, they also become contaminated and severe nervous system injuries may result from it. The main sources of mercury pollution are gold mining and the use of substances derived from it in industry and agriculture.

Question 2.
Besides mercury, which other heavy metals cause toxic pollution?
Answer:
Examples of other heavy metals that cause toxic pollution are lead, cadmium and chromium.

Question 3.
What are persistent organic poliutants (POPs)?
Answer:
POPs, or persistent organic pollutants, are toxic substances formed from organic compounds. POPs are produced in several industrial processes, such as the production of PVC, paper whitened by chlorine, herbicides, insecticides and fungicides, as well as in the incineration of waste. Examples of POPs are dioxins, furanes, chlordane, DDT, dieldrin, heptachlor, toxaphene and hexachlorobenzene.

POPs are toxic and highly harmful since, like the heavy metals, they are bioaccumulative, meaning that they are not broken down by the body and accumulate even more in each following trophic level of the food chain. In humans, POPs can cause cancer and nervous, immune and reproductive disorders.

Question 4.
Is the upward movement of warm air good or bad for the dissipation of pollutants?
Answer:
The upward movement of warm air is a natural method of dispersing pollutants. The air near the ground is hotter because the sun heats the soil and the soil heats the air nearby. Since it is less dense, the warm air tends to move towards higher and colder strata of the atmosphere. Such movement helps to disperse pollutants.

Question 5.
Why does thermal inversion increase air pollution? What harm can thermal inversion cause to humans?
Answer:
Thermal inversion confines a layer of pollutants at low altitude, which otherwise would have been dispersed by the natural upward movement of warm air. The solid particles present in the atmosphere cause health problems, such as the exacerbation of asthma and other pulmonary diseases, coughing, respiratory unease and eye discharges. Over time, pollution can also trigger the appearance of cardiovascular and neoplastic diseases.

Question 6.
What are the health consequences of air pollution?
Answer:
Air pollution increases the risk of respiratory and heart disease in the population. Both short and long term exposure to air pollutants have been associated to health impacts. More severe impacts affect people who are already ill. Children, the elderly and poor people are more susceptible.

Question 7.
What is pathogen pollution?
Answer:
Pathogen pollution refers to the introduction of disease-causing microbes(pathogens) and/or their hosts (infected individuals) to new locations around the world. European bird species, including pigeons and the house sparrow, for example, introduced West Nile virus to the United States.

Question 8.
What is an emerging infectious disease (EID)?
Answer:
EIDs include diseases that have jumped from wildlife populations to humans, diseases that have become more frequent, and diseases that are entirely new to science. Examples of EIDs include HIV/AIDS, West Nile virus, and SARS. Lung diseases are some of the most common medical conditions in the world. Tens of millions of people suffer from lung disease in the U.S. Smoking, infections, and genetics are responsible for most lung diseases. The lungs are part of a complex apparatus, expanding and relaxing thousands of times each day to bring in oxygen and expel carbon dioxide. Lung disease can result from problems in any part of this system.

Question 9.
Write the health effect on air pollution.
Answer:
Air Pollution Effects :

1. Reduced lung functioning
2. Irritation of eyes, nose, mouth and throat
3. Asthma attacks
4. Respiratory symptoms such as coughing and wheezing
5. Increased respiratory disease such as bronchitis
6. Reduced energy levels
7. Headaches and dizziness
8. Disruption of endocrine, reproductive and immune systems
9. Neurobehavioral disorders
10. Cardiovascular problems
11. Cancer
12. Premature death.

Question 10.
Write the health effect on water pollution.
Answer:
Water Pollution Effects :

1. Waterborne diseases like typhoid,jaundice,cholera
2. Hepatitis, encephalitis, gastroenteritis, diarrhoea, vomiting, and stomach aches
3. Cancer, including prostate cancer and non-Hodgkin’s lymphoma
4. Hormonal problems that can disrupt reproductive and developmental processes
5. Damage to the nervous system
6. Liver and kidney damage
7. Damage to the DNA

Question 11.
Write the health effect on soil pollution.
Answer:
Soil Pollution Effects :

1. Lead in soil is especially hazardous for young children causing developmental damage to the brain
2. Mercury can increase the risk of kidney damage; cyclodienes can lead to liver toxicity
3. Causes neuromuscular blockage as well as depression of the central nervous system
4. Also causes headaches, nausea, fatigue, eye irritation and skin rash
5. Causes cancers including leukaemia

Long Answer Type Questions : 5 Marks

Question 1.
What do you mean by overpopulation? Write its causes.
Overpopulation
Answer:
Overpopulation is an undesirable condition where the number of existing human population exceeds the carrying capacity of Earth.Overpopulation is caused by number of factors. Reduced mortality rate, better medical facilities, depletion of precious resources are few of the causes which results in overpopulation. It is possible for a sparsely populated area to become densely populated if it is not able to sustain life.
Causes of Overpopulation
Decline in the Death Rate : At the root of overpopulation is the difference between the overall birth rate and death rate in populations. If the number of children born each year equals the number of adults that die, then the population will stabilize.

Better Medical Facilities : Following this came the industrial revolution. Technological advancement was perhaps the biggest reason why the balance has been permanently disturbed. Science was able to produce better means of producing food, which allowed families to feed more mouths.

More Hands to Overcome Poverty : For thousands of years, a very small part of the population had enough money to live in comfort. The rest faced poverty and would give birth to large families to make up for the high infant mortality rate.

Families that have been through poverty, natural disasters or are simply in need of more hands to work are a major factor for overpopulation.

Technological Advancement in Fertility Treatment : With latest technological advancement and more discoveries in medical science, it has become possible for couple who are unable to conceive to undergo fertility treatment methods and have their own babies.

Immigration : Many people prefer to move to develop countries like US, UK, Canada and Australia where best facilities are available in terms of medical, education, security and employment. The end result is that those people settle over there and those places become overcrowded.

Lack of Family Planning : Most developing nations have large number of people who are illiterate, live below the poverty line and have little or no knowledge about family planning. Getting their children married at an early age increase the chances of producing more kids.

Question 2.
Write the effects and solution of overpopulation.
Answer:
Effects of Overpopulation
Depletion of Natural Resources : The effects of overpopulation are quite severe. The first of these is the depletion of resources. The Earth can only produce a limited amount of water and food, which is falling short of the current needs. Most of the environmental damage being seen in the last fifty odd years is because of the growing number of people on the planet.

Degradation of Environment : With the overuse of coal, oil and natural gas, it has started producing some serious effects on our environment. Rise in the number of vehicles and industries have badly affected the quality of air. Rise in amount of CO₂ emissions leads to global warming. Melting of polar ice caps, changing climate patterns, rise in sea level are few of the consequences that we might we have to face due to environment pollution.

Conflicts and Wars : Overpopulation in developing countries puts a major strain on the resources, it should be utilizing for development. Conflicts over water are becoming a source of tension between countries, which could result in wars. It causes more diseases to spread and makes them harder to control. Starvation is a huge issue facing the world and the mortality rate for children is being fuelled by it. Poverty is the biggest hallmark we see when talking about overpopulation.

Rise in Unemployment : When a country becomes overpopulated, it gives rise to unemployment as there fewer jobs to support large number of people. Rise in unemployment gives rise to crime as people will steal various items to feed their family and provide them basic amenities of life.

High Cost of Living: As difference between demand and supply continues to expand due to overpopulation, it raises the prices of various commodities including food, shelter and healthcare. This means that people have to pay more to survive and feed their families.
Solutions to Overpopulation

Better Education : One of the first measures is to implement policies reflecting social change. Educating the masses helps them understand the need to have one or two children at the most. Families that are facing a hard life and choose to have four or five children should be discouraged. Family planning and efficient birth control can help in women making their own reproductive choices.

Making People Aware of Family Planning : As population of this world is growing at a rapid pace, raising awareness among people regarding family planning and letting them know about serious after effects of overpopulation can help curb population growth.

Tax Benefits or Concessions : Government of various countries might have to come with various policies related to tax exemptions to curb overpopulation. One of them might be to waive of certain part of income tax or lowering rates of income tax for those married couples who have single or two children.

Knowledge of Sex Education : Imparting sex education to young kids at elementary level should be must. Most parents feel shy in discussing such things with their kids which result in their children going out and look out for such information on internet or discuss it with their peers. Mostly, the information is incomplete which results in sexually active teenagers unaware of contraceptives and embarrassed to seek information about same. It is therefore important for parents and teachers to shed their old inhibitions and make their kids or students aware of solid sex education.

Question 3.
Describe about the Lung Diseases Affecting the Airways
Answer:
The trachea (windpipe) branches into tubes called bronchi, which in turn branch to become progressively smaller tubes throughout the lungs.
Diseases that affect the airways include :
Asthma : The airways are persistently inflamed and may occasionally spasm, causing wheezing and shortness of breath. Allergies, infections, or pollution can trigger asthma’s symptoms.

Chronic obstructive pulmonary disease (COPD) : Lung conditions defined by an inability to exhale normally, which causes difficulty breathing.

Chronic bronchitis : A form of COPD characterized by a chronic productive cough.

Emphysema : Lung damage allows air to be trapped in the lungs in this form of COPD. Difficulty blowing air out is its hallmark.

Acute bronchitis : A sudden infection of the airways, usually by a virus.
Cystic fibrosis : A genetic condition causing poor clearance of mucus from the bronchi. The accumulated mucus results in repeated lung infections.

Question 4.
Describe about the Lung Diseases affecting the air sacs (Alveoli).
Answer:
The airways eventually branch into tiny tubes (bronchioles) that dead-end into clusters of air sacs called alveoli. These air sacs make up most of the lung tissue. Lung diseases affecting the alveoli include :
Pneumonia : An infection of the alveoli, usually by bacteria.
Tuberculosis: A slowly progressive pneumonia caused by the bacteria Mycobacterium tuberculosis.

Emphysema results from damage to the fragile connections between alveoli. Smoking is the usual cause. (Emphysema also limits air flow, affecting the airways as well.)

Pulmonary edema : Fluid leaks out of the small blood vessels of the lung into the air sacs and the surrounding area. One form is caused by heart failure and back pressure in the lungs’ blood vessels ; in another form, direct injury to the lung causes the leak of fluid.

Lung cancer has many forms, and may develop in any part of the lungs. Most often this is in the main part of the lung, in or near the air sacs. The type, location, and spread of lung cancer determine the treatment options.

Acute respiratory distress syndrome (ARDS): Severe, sudden injury to the lungs caused by a serious illness. Life support with mechanical ventilation is usually needed to survive until the lungs recover.

Pneumoconiosis : A category of conditions caused by the inhalation of a substance that injures the lungs. Examples include black lung disease from inhaled coal dust and asbestosis from inhaled asbestos dust.

Question 5.
Describe about the Lung Diseases affecting the interstitium.
Answer:
The interstitium is the microscopically thin, delicate lining between the lungs’ air sacs (alveoli). Tiny blood vessels run through the interstitium and allow gas exchange between the alveoli and the blood. Various lung diseases affect the interstitium:
Interstitial lung disease (ILD) : A broad collection of lung conditions affecting the interstitium. Sarcoidosis,idiopathic pulmonary fibrosis, and autoimmune disease are among the many types of ILD.
Pneumonias and pulmonary edemas can also affect the interstitium.

Question 6.
Describe about the Lung Diseases affecting blood vessels.
Answer:
The right side of the heart receives low-oxygen blood from the veins. It pumps blood into the lungs through the pulmonary arteries. These blood vessels can suffer from disease, as well.

Pulmonary Embolism (PE) : A blood clot (usually in a deep leg vein,deep vein thrombosis) breaks off, travels to the heart, and is pumped into the lungs. The clot lodges in a pulmonary artery, often causing shortness of breath and low blood oxygen levels.

Pulmonary hypertension : Various conditions can lead to high blood pressure in the pulmonary arteries. This can cause shortness of breath and chest pain. When no cause is identified, the condition is called idiopathic pulmonary arterial hypertension.

Question 7.
Describe about the Lung Diseases affecting the pleura.
Answer:
The pleura is a thin lining that surrounds the lung and lines the inside of the chest wall. A tiny layer of fluid allows the pleura on the lung’s surface to slide along the chest wall with each breath. Lung diseases of the pleura include :
Pleural effusion : Fluid collects in the normally tiny pleura space between the lung and the chest wall. Pneumonia or heart failure is usually responsible. If large, pleural effusions can impair breathing, and should be drained.
Pneumothorax : Air may enter the space between the chest wall and the lung, collapsing the lung. To remove the air, a tube is typically inserted through the chest wall.
Mesothelioma : A rare form of cancer that forms on the pleura. Mesothelioma tends to emerge several decades after asbestos exposure.

Question 8.
Describe about the Lung Diseases affecting the chest wall.
Answer:
The chest wall also plays an important role in breathing. Muscles connect the ribs to each other, helping the chest to expand. The diaphragm descends with each breath in, also causing chest expansion.
Obesity hypoventilation syndrome : Extra weight on the chest and abdomen makes it difficult for the chest to expand. Serious breathing problems can result.
Neuromuscular disorders : Poor function in the nerves controlling the respiratory muscles causes difficulty of breathing. Amyotrophic lateral sclerosis and myasthenia gravis are examples of neuromuscular lung disease.

Multiple Choice Questions : 1 Mark

Question 1.
Who among the following are resource creating factors as well as resources themselves?
(a) Animals
(b) Plants
(c) Human beings
(d) Nature
Answer:
(c) Human beings

Question 2
In which of the following instances does a natural event like a flood or Tsunami become a “disaster”?
(a) Only when they affect a crowded village or town
(b) When the natural events are of great intensity
(c) When they happen in the environment
(d) When they affect large uninhabited areas
Answer:
(a) Only when they affect a crowded village or town

Question 3.
The numbers, distribution, growth and characteristics of which of the following provide the basic background for understanding and appreciating all aspects of the environment?
(a) Natural resource
(b) Population
(c) Flora
(d) Fauna
Answer:
(b) Population

Question 4.
Why is it important to know how many people are there in a country, where do they live, how and why their numbers are increasing and what are their characteristics?
(a) Population is the pivotal element in social studies
(b) To exploit the natural resources of the country
(c) Human beings are producers and consumers of resources
(d) None of these
Answer:
(c) Human beings are producers and consumers of resources

Question 5.
From which of the following do we get information regarding the population of our country?
(a) Text books
(b) Survey of India
(c) Census
(d) Geological Survey of India
Answer:
(c) Census

Question 6.
Which of the following is a major concern of study about the population of a country?
(a) Population size and distribution
(b) Population growth and processes of population change
(c) Characteristics or qualities of the population
(d) All of these
Answer:
(d) All of these

Question 7.
The average number of persons per unit area, such as a square kilometre, is termed as which of the following?
(a) Population distribution
(b) Population density
(c) Absolute population
(d) Population growth
Answer:
(b) Population density

Question 8.
Which of the following reasons is responsible for uneven population distribution in India?
(a) Variations in topography or relief in different parts of India
(b) Variations in climate and rainfall distribution
(c) Variations in the rate of industrialisation and urbanisation
(d) All of the above
Answer:
(d) All of the above

Question 9.
When did the National Population Policy come into effect?
(a) 2001
(b) 1947
(c) 1952
(d) 2000
Answer:
(d) 2000

Question 10.
The unfavourable alteration of environment due to human activities is termed as
(a) ecological disturbance
(b) catastrophe
(c) ecological degradation
(d) pollution
Answer:
(d) pollution

Question 11.
Which of the following is the best indicator of SO₂ pollution
(a) bryophyte
(b) pteridophyte
(c) lichen
(d) algae
Answer:
(c) lichen

Question 12.
Heavy dust can cause
(a) leaf blights
(b) opening of stomata
(c) closure of stomata
(d) browning of leaves
Answer:
(c) closure of stomata

Question 13.
Which of the following is the major cause of pollution
(a) Plants
(b) man
(c) fungi
(d) hydrocarbon gases
Answer:
(d) hydrocarbon gases

Question 14.
Minamata disease was caused by pollution of water by
(a) mercury
(b) lead
(c) tin
(d) methyl isocyanate
Answer:
(a) mercury

Question 15.
BOD stands for
(a) biotic oxidation demand
(b) biological oxidation demand
(c) biological oxygen demand
(d) biochemical oxygen demand
Answer:
(c) biological oxygen demand

Question 16.
A river with high BOD value is
(a) highly polluted
(b) highly clean
(a) highly productive
(d) none of these
Answer:
(a) highly polluted

Question 17.
5 June is observed as
(a) world forest day
(b) world environment day
(a) world wildlife day
(d) world population day
Answer:
(b) world environment day

Question 18.
Cement factory labourers are prone to
(a) leukemia
(b) bone marrow disease
(c) asbestosis
(d) cytosilicosis
Answer:
(d) cytosilicosis

Question 19.
Noise is measured using sound meter and the unit is
(a)) hertz
(b) decibel
(c) joule
(d) sound
Answer:
(b) decibel

Very Short Answer Type Questions : 1 Mark

Question 1.
What is overpopulation?
Answer:
For a period of time, excess population in an area.

Question 2.
Which gas mostly causes global warming?
Answer:
CO₂

Question 3.
Which situation causes scarcity of food?
Answer:
Overpopulation.

Question 4.
Mention two situation due to over population.
Answer:
Deforestation, shrinkage of Agricultural land.

Question 5.
Mention two diseases of water borne.
Answer:
Hepatitis, Typhoid.

Question 6.
Name two diseases of food borne,
Answer:
Cholera, Aspergilosis.

Question 7.
Mention two ariborne diseases.
Answer:
Influenza, Pneumonia.

Question 8.
What is the cause of minamata disease?
Answer:
Due to excess amount of mercury.

Question 9.
Name two lung diseases.
Answer:
Asthma, Bronchitis.

Question 10.
Name the agent causing cancer.
Answer:
Carcenogen.

Question 11.
Name two causative agents for lung cancer.
Answer:
Pesticides, Food adulteration, smoke from industry.

Question 12.
Name two agents for Asthma.
Answer:
Pollens, dust, fungus.

Question 13.
Name the disease due to lead pollution.
Answer:
Dislexia.

Question 14.
Name the causative agent of Aspergilosis.
Answer:
Fungus.

Detailed explanations in West Bengal Board Class 10 Life Science Book Solutions Chapter 5B Environmental Pollution offer valuable context and analysis.

WBBSE Class 10 Life Science Chapter 5B Question Answer – Environmental Pollution

Short Answer Type Questions : 2 Marks

Question 1.
Why does the concentration of harmful substances increase significantly in certain location?
Answer:
Atmospheric diffusion of air is minimum at elevation of 3000 metres above earth’s surface. Many pollutants do not rise above 600 metre. Mixing and dilution of pollutants are often hampered by natural and artificial barriers. Therefore, concentration of harmful substances often becomes high in certain locations.

Question 2.
What is Acid rain?
Answer:
Oxidation of sulphur in the fossil fuels mainly produces sulphur dioxide and sulphur trioxide, which are harmful. These gases react with water to form sulphuric or sulphurous acids. The acids, when precipitated as rain or snow, create acid rain or acid precipitation.

Question 3.
How has the average temperature of the earth remained constant?
Answer:
The average temperature of the earth has remained fairly constant because there is a balance between the amount of energy received and that reflected from the earth back into space.

Question 4.
Why does the concentration of pollutants become high in certain location?
Answer:
Increase in the concentration of pollutants takes place because mixing a dilution of pollutants is hampered by artificial barriers, i.e. diffusion of pollutants above 300 metres above earth’s surface is minimal. Many pollutants do not rise above 600 metres.

Question 5.
What are particulate pollutants?
Answer:
Pollutants in the form of solid or liquid particles are known as particulate pollutants.

Question 6.
Name the major pollutants emitted by motile commercial source.
Answer:
The major pollutants emitted by motile commercial sources are carbon monoxide (77.2%), nitrogen oxides (7.7%), hydrocarbons (13.7%) and a small fraction of lead products.

Question 7.
What is the effect of sulphur dioxide on human?
Answer:
Sulphur dioxide is highly soluble in water. It enters soft tissues and causes dryness of the mouth, scratchy throat and irritation of the eyes.

Question 8.
Name the respiratory problems caused by polluted air?
Answer:

1. Bronchitis
2. Emphysema
3. Lung cancer, especially in children.

Question 9.
Name two ways by which air pollutian is controlled at the source.
Answer:
(i) By separating the pollutants from the harmless gases, and (ii) By converting the pollutants into innocuous products.

Question 10.
What is BOD?
Answer:
Biochemical Oxygen Demand (BOD) is the amount of oxygen taken up by micro-organisms in the water.
BOD is measured by keeping a sample of water containing known amounts of oxygen for five days at 20° C in the dark. At the end of five days the oxygen content is measured again.
A high level of BOD indicates intense level of microbial pollution, signifying the presence of high level of organic pollutants.

Long Answer Type Questions : 5 Marks

Question 1.
What do you mean by soil pollution?
Answer:
Soil pollution :

• Soil pollution, also called land pollution is addition or removal of nutrients which reduces the productivity of soil.
• The substances which are responsible for the reduction of soil productivity are called as soil pollutants.
• Soil pollutants alter the basic composition of the soil that may kill important soil organisms.
• There are two types of soil pollution-positive and negative soil pollution.
• When there is addition of undesirable substance in the soil then it is called as positive pollution.
• When there is reduction of soil fertility due to loss of its top layer, it is called as negative pollution.
• Negative pollution is also sometimes called third pollution or landscape pollution in which fertile land is converted into barren areas by addition of solid wastes like leather goods, spoiled food items etc.

• Pesticides, fertilizers, chemicals and radioactive wastes are the main sources of soil pollution.
• Excessive use of fertilizers causes soil deterioration through decrease of natural mircoflora. Leaching down causes pollution of underground water (third poison).
• Salts entering crop plants in excess may prove harmful.
• For example, nitrate rich leaves, fruits and water produce nitrite in alimentary canal that enters blood, combines with haemoglobin forming met-haemoglobin and reducing oxygen transport. It may prove fatal in infants.
• Soild wastes from municipalities and industries are often dumped temporarily over land. During rains heavy metals and toxic chemicals are washed down into soil and pollute the same.
• Quality of land also deteriorate due to deforestation, desertification, water logging and flooding.

Question 2.
What do you mean by pesticides?
Answer:
Pesticides include insecticides, fungicides, algicides, rodenticides and weedicides. Along with target organism they harm nontarget organism as well. This destroys the ecosystem of the soil.
Pesticides are of following types :

• Organochlorines/Chlorinated Hydrocarbons : DDT, BHC, aldrin, dieldrin and endrin. They are persistent and show biomagnification and thus prove harmful to higher trophic level organisms.
• Organo-pesticides : Degradable but toxic to workers, e.g. malathion, parathion, carbamates.
• Inorganic pesticides : They contain arsenic and sulphur and are persistent. Hence their use is highly restricted.
• Weedicides : They are persistent and harmful.

Question 3.
What do you mean by solid wastes?
Answer:
Solid wastes :
Solid wastes are discarded or left over solid materials. The terms rubbish and trash are often used interchangeably for solid waste materials. The various sources of solid wastes are municipal wastes, industrial wastes, mining wastes, hazardous wastes, defunct ships and electronic wastes.

Municipal wastes are solid wastes from homes, shops, offices, schools, street and road sweepings which are collected and disposed off by municipalities. The major components are waste paper, textiles, leather, metals, glass, plastic and polythene, food wastes etc.

Industrial wastes include scrap, effluents, sludge and flyash. Flyash is fall out from industrial emissions especially thermal plants which is often mixed with smoke. It consists of oxides of silica, aluminium and iron alongwith small quantities of heavy metals.

Mining wastes include mine dust, rock tailings, slack and slag. Toxic metals and chemicals present in the mining wastes destroy vegetation and produce many deformities in animals and human beings.

Opencast mining is a process where the surface of the earth is dug open to bring out the underground mineral deposits completely devastating the topsoil and contaminates the area with toxic metals and chemicals.

Hazardous solid wastes are generated by industries producing pesticides, rubber, dyes, chemicals, paper and metals. They are not only highly toxic to humans and other organisms but are also corrosive and highly inflammable.

Hospital wastes are full of hazardous materials like infected organic wastes, pathogens, pathogen carriers, harmful chemicals, needles, syringes, vials etc. along with some disinfectants.

Electronic wastes are irreparable computers, mobiles and other electronic goods often called e-wastes. Electronic wastes are generally sent to developing countries like India, China and Pakistan for extraction of metals through recycling.

Question 4.
Write the control of soil pollution and solid wastes.
Answer:
Control of soil pollution :

• Soil pollution can be checked by improving the disposal wastes, appropriate use of chemical fertilizers and use of biological pest.control.
• The most important measure to check land degradation is restoration of forest, crop rotation, improved drainage etc.

Control of solid wastes :

It involves collection and categorisation of wastes, transport to disposal site and disposal of waste. Disposal of waste consists of recovery and recycling, source reduction, burning and dumping.
The articles which can be recovered and recycled are tins, cans and other metal wastes, glass, plastic, polyethylene, rags, paper and cardboard.
Metal waste can be melted and purified. Broken glass is used similarly to form new glass.
Waste polyethylene is melted and recast to form new polyethylene.
In source reduction garbage and other organic wastes are taken out of urban areas and used for formation of compost, biogas and manure.
On small scale vermiculture is practised to form manure and compost.
All types of organic wastes of a town are used to prepare a manure called compost. In composting the sludge obtained after primary treatment of sewage alongwith other wastes are allowed to decompose in an open space. In 4 6 months compost is ready for use as a manure.
Cowdung and other organic wastes of farm houses can now be profitably placed in gobar gas plants which not only enrich manure but also provide gas for domestic use.
Burning is combustion of solid waste containing organic compounds in open places. It, however, produces offensive odours and air pollutants. Better methods are incineration and pyrolysis.
Incineration : It is controlled aerobic combustion of wastes inside chambers at temperature of 900-1300° C.
Pyrolysis : It is combustion inside chambers in the absence of oxygen at a temperature of 1650° C. It does not yield pollutant.
Dumping is piling of waste on selected low lying land. It is of two types, open and sanitary.
In open dumping (open landfill), waste is accumulated on uncovered low lying area and it is periodically burnt or compressed at intervals to reduce its bulk.
In sanitary dumping (sanitary landfill), the waste is pulverised, compacted or covered over by a layer of earth.

Question 5.
What do you mean by noise pollution with their sources, effect and control measures?
Answer:
Noise Pollution :
Unpleasent loud sound is called as noise (also called slow killer) and disturbing level of noise is known as noise pollution.
Annoying noise from industries, transport vehicles, agricultural machines, defence equipments, domestic gadgets, music systems, public address systems and demonstrations are various causes of noise pollution.
Noise pollution is measured in decibels.
Generally sound above 80 dB is termed as noise.
A sound more than 115 dB is harmful to the ears.
Moderate conversation has a noise value of 60 dB; scooter, buses, trucks etc. create noise of about 90 dB; jets of about 150 dB and rockets of 180 dB.
A decibel value above tolerable limit of noise is about 140 dB.
Sources of noise pollution

Main sources of noise pollution are:
Various industries such as textile mills, printing presses, engineering establishments.
Agricultural machines like tractors, harvesters, tubewells etc.
Defence equipment such as tanks, artillery, rocket launching, shooting practices, explosions.
Entertaining equipment like radios, record players, television sets.
Domestic gadgets such as desert coolers, air conditioners, vacuum cleaners, exhaust fans, mixers, pressure cooker.
Public address systems like loud speakers.
Transport vehicles like scooters, motor-cycles, ear, buses, trucks, trains, jet planes.
Dynamite blasting.
Crackers used at occasions like marriages and festivals.
Bull dozing, stone crushing, construction work etc.
Effects of noise pollution
Auditory effects
Auditory fatigue appears in the 90 dB region and greatest at 4000 Hz. It may be associated with side effects such as whistling and buzzing in the ears.
Deafness or hearing loss is the most serious pathological effect.
Further, it has been found that prolonged noise at 95 dB will produce deafness, nervous tension and rise in blood pressure.
A regular exposure to sound of 80 dB reduces hearing by 15 dB in 10 years.
Noise becomes uncomfortable above 100 dB.
Non-auditory effects
Noise interferes with speech communication. In everyday life the frequencies causing most disturbance to speech communication lie in the 300-500 Hz range. Such frequencies are commonly present in noise produced by road and air traffic.

The first effect of noise pollution is anxiety and stress reactions. Annoyance is primarily a psychological response. Neurotic people are more sensitive to noise than balanced people.

Work men exposed to higher intensities of noise in occupational capacities, were often irritated, short tempered and impatient and more likely to resort to agitation and disrupt production.
A number of temporary physiological changes occur in the human body as a direct result of noise exposure. These are a rise in blood pressure, a rise in intracranial pressure, .an increase in heartrate and breathing and an increase in sweating.
Efficiency to work decreases by noise pollution. Noise stimulates the secretion of adrenaline which increases irritability, nervousness, neuromuscular tension and feeling of fatigue, so decreasing the working efficiency.
Noise causes vasoconstriction which decreases the blood flow.
Control of noise pollution
For controlling the noise pollution, several methods have been suggested.
In metropolitan areas green belt vegetation and open space in general may have a great value in noise control as in air purification.
Green muffler scheme involves the growing green plants along roadsides to reduce noise pollution.
The enclosure of machinery with sound absorbing materials is an example of the industrial noise reduction pattern already practised by industries in advanced countries. Protection to workers can be provided through wearing devices such as a ear-plugs.
Specific legislation and regulations should be proposed for designing and operation of machines, vibrations control, sound-proof cabins and sound-absorbing materials.

Question 6.
What do you mean by ozone layer depletion and its effects?
Answer:
Ozone layer depletion
Stratosphere have a thick layer of ozone called ozonosphere which protects life on earth from harmful effects of UV radiations. Thickness of ozone is measured in Dobson unit.
Ozone in the Earth’s atmosphere is generally created by ultraviolet light striking oxygen molecules, which consist of two oxygen atoms (O₂), creating two single oxygen atoms, known as atomic oxygen. The atomic oxygen then combines with a molecule of O₂ to create ozone, O₃.
In stratosphere ozone is formed and photodissociated. It dissipates the energy of UV radiations.

Ozone absorbs most of the ultraviolet radiation, so it shields earth against biologically harmful solar radiations.
Ozone depletion refers to the phenomenon of reduction in the amount of ozone in the stratosphere. The depletion of O₃ layer by human activities may have serious implications and this has become a subject of much concern over the last few years.
Depletion in the concentration of ozone over a restricted area as over Antarctica is called ozone hole. An ozone hole was discovered over Antarctica by Farman et al, 1985 who also coined the term.
Spring time depletion of ozone is due to action of sunlight over pollutants which release chemicals (e.g., chlorine) that destroy ozone.

Thinning of ozone shield will increase the amount of UV-B radiation reaching the earth which will result in 2,50,000 more persons catching skin cancer and 5,00,000 more persons becoming blind.
Ozone depleting substances (ODS) are substances which react with ozone present in the stratosphere and destroy the same.
The ozone layer is destroyed by aerosols. Aerosols are certain chemicals released into the air with force in the form of mist or vapour.
Major aerosol pollutant present in jet plane emissions is fluorocarbon.
Besides chloroflourocarbons or CFCs (CCl₂ F₂\right. and CCl₃ F; used as coolants in air conditioners and refrigerators, cleaning solvents, aerosol propellants and foam insulation), nitrogen oxides (coming from fertilisers) and hydrocarbons are also responsible for O₃ depletion.

CFC produces active chlorine in the presence of UV radiation. These destroy ozone, converting it into oxygen. The reactions were discovered by Molina and Rowland (1974, Noble Prize, 1995 along with Crutzen). Chlorine action over ozone is chainamictics.

Effects of ozone depletion
Ultraviolet radiations are of three types UV-C (100 280 nm), UV-B (280 320 nm) and UV-A (320-390 nm).
The intermediate or UV-B are harmful as well as cayable of deeg genetration.
Thinning of ozone layer increases the amount of UV-B radiations reaching the earth.
Researches show that surface UV-B radiation inhibits photosynthesis in Antarctic phytoplanktons. This, in turn, can affect the whole food chain of organisms that depend on phytoplankton. Elevated levels of UV-B radiation affect photosynthesis, as well as damage nucleic acid in living organisms.

The various other important effects of ozone depletion are :
Cornea absorbs UV-B radiations and becomes inflamed. The disorder is called “snow blindness” cataract. It leads to diminishing of eye sight, photoburning and later permanent damage to cornea that results in actual cataract.
UV-B radiations damage skin cells, cause ageing of skin and skin cancer.
Damage of nucleic acids will increase resulting in higher number of mutatinosa.
UV radiations inhibit photosynthesis by affecting photosynthetic machinery.
Decreased photosynthetic activity will increase CO₂ concentration of the atmosphere resulting in global warming.
Both marine and terrestrial food chains will be disturbed.

Question 7.
What do you mean by greenhouse effect? Write its effect.
Answer:
Greenhouse effect :
The atmospheric greenhouse gases forms a blanket like covering around the earth. It controls the escape of heat from the earth’s surface to outer space and keeps it warm and hostile. This phenomenon is known as greenhouse effect.
It is actually a warming effect found in greenhouse by allowing solar radiations to pass in but preventing long wave heat radiations to pass out due to glass panels, water vapours and carbon dioxide. Because of it greenhouses are used for growing tropical plants in temperate areas.
The capacity of atmosphere to keep the Earth warm depends on the amount of greenhouse gases the gases which are transparent to solar radiation but retain and partially reflect back long wave heat radiations.
Greenhouse gases radiate a part of this solar energy back to the earth. The phenomenon is called greenhouse flux. Because of greenhouse flux, the mean annual temperature of earth is 15° C.
Recently the concentration of greenhouse gases has started rising resulting in enhanced greenhouse effect that is resulting in increasing the mean global temperature. It is called global warming.
The various greenhouse gases are CO₂ (warming effect 60% ), CH₄ (effect 20%), chlorofluorocarbons or CFCs (14%) and nitrous oxide (N₂ O 6%). Others of minor significance are water vapour and ozone.

Effects of green house gases
CO₂ fertilization : Increase in CO₂ concentration increases the rate of photosynthesis especially in C₃ plants. Amount of stomatal conductance will decrease resulting in lower rate of transpiration. There will be greater root growth, more mycorrhizal development and increase in N₂ fixation in root nodules. So that plants will grow more successfully in regions of water scarcity and nutrient poor soils. However, these beneficial effect will be nullified by negative effects of global warming.
Global warming : It is believed that increase in concentration of greenhouse gases has resulted in rise of atmospheric temperature. Rise in temperature will be slight in tropics, moderate in middle latitudes and maximum in polar regions (World Climate Programme, WCP, 1988).

Global warming has many fold effects as :
Effect on weather and climate: There is increase in average temperature by 1.4-5.8° centigrade by the year 2100 . Warming of atmosphere increases its moisture containing capacity. All these are responsible for change in precipitation pattern. This climatic change is harmful for human health.

Sea level change : The global warming is responsible for increase in sea level and melting of-glaciers and Greenland ice sheets.
Effects on range of species distribution : Due to increase in global warming, many species are expected to shift poleward or towards high elevation in mountain regions.

Food production : Increase in temperature causes extensive growth of weeds which ultimately decrease crop production.
Some strategies should be followed to deal with global warming:
Vegetation cover should be increased for photosynthetic utilization of carbon dioxide.
Chlorofluorocarbon should be replaced with some other substitute having little effect on global warming.
Reducing the use of nitrogen fertilizers to reduce nitrous oxide emission.
Minimizing the use of fossil fuel to reduce the greenhouse gas emission.

Question 8.
What do you mean by air pollution?
Answer:
Air Pollution

1. Oxides of Carbon : Carbon monoxide, Carbon dioxide
2. Oxides of Nitrogen : Nitrogen oxide and Nitrogen dioxide
3. Oxides of Sulphur : Sulphur dioxide and Sulphur trioxide.
4. Photochemical oxidants : Ozone, PAN (Peroxyacyl nitrate) aldehydes and other organic compounds produced by photochemical reactions between primary pollutants.
5. Hydrocarbons : Products of incomplete combustion of automobile fuel.
6. Particulate Matter : Fine solid and liquid particles, like flyash and soot from burning of coal; dust particles from industries.
7. Chemical released in vapour form as fluorocarbons, chloro-fluoromethanes.

Sources :

1. Effect-on plants : Like Chlorosis, necrosis, bleaching, premature fall of leaves, reducing photosynthetic capacity etc. leading to the damage of the crops.
2. Effects on animals and man : Like dryness of skin, congestion of respiratory tract, reduction in oxygen transport, damage to nervous system; chromosomal aberrations and cancer.
3. Climatic changes: Like Green House effect leading to global warming. Depletion of ozone layer and consequent increase in ultraviolet radiations which can cause mutations and cancer.
4. Aesthetic loss: Like spoiling the beauty of nature.

Effects :

1. Stationery combustion sources
2. Mobile combustion sources
3. Industrial processes and
4. Other sources

Question 9.
What are the sources and effects of Water Pollution?
Answer:

Sources :

1. Community waste water : as discharges from homes and commercial and industrial establishments connected to municipal sewage system.
2. Industrial waste : as chemical wastes which are discharged into rivers or streams.
3. Agricultural sources: addition of fertilisers to crops results in water pollution in water-bodies.
4. Marine pollution : navigational discharges of oil grease and petroleum products, detergents, sewage and garbage including radioactive wastes.

Effects :
The main effects of water pollution are:

1. Compounds of mercury, arsenic and lead are poisonous and they may affect the waste treatment plant.
2. Organic sulphur compounds interfere with nitrification.
3. Inorganic nitrates and phosphates stimulate excessive plant growth in lakes and reservoirs.
4. The organochlorines from pesticides are highly persistent and pass through food chains. They mainly accumulate in the nervous tissue and affect the nervous system.
5. The broad spectrum pesticides used currently cause mass destruction of aquatic life through their accidental release or excessive use.
6. Due to the presence of very fine suspended matter, water becomes unclear, unfit for drinking and industrial use.
7. Presence of free chlorine, phenol, hydrogen, ammonia, algae and microorganisms make it bad in taste and odour, and cause infection too.
8. Formation of foam due to presence of soaps, detergents and alkalies.

Question 10.
What are the effects of radioactive pollution?
Answer:
Effects of radioactive pollution
The effect of radioactive pollutants depends on :
Strength of radiations
Rate of diffusion and deposition of the pollutants
The length of time for which the tissue is exposed to radiation
Half-life of pollutants. Environmental factors (wind, temperature, rainfall) also influence their effects.
Radioactive pollution affects all the organisms including humans. It causes cancer, mutations and even death in humans and animals.
On the basis of their action on cells, radiations are divided into two categories non-ionising radiations and ionising radiations.
Non ionising radiation refers to any type of electromagnetic radiation, that does not carry enough energy per quantum to ionize atoms or molecules.
Near ultra-violet, visible light, infrared, microwave, radio waves are all examples of non-ionising radiations.
Ionising radiation consists of electromagnetic waves that are energetic enough to detach electrons from atoms or molecules ionising them.
Ionising radiations include ultra-violet rays. X-rays, cosmic rays and atomic radiations which damage the living cells by ionisation (shifting the electrons from one to other bio-molecule). Ultra-violet rays (100-300 nm) are known to cause sunburn, snow blindness, inactivation of organic bio-molecules, formation of thymine-dimer in DNA and skin cancer.
Strontium-90 behaves like calcium in biogeochemical cycling of materials in ecosystem. It accumulates in the bones to cause bone cancer and tissue degeneration in a number of organs.
Iodine-131 damages WBCs, bone marrow, spleen, lymph nodes, skin cancer, sterility and defective eye sight.
Radioactive iodine may also cause cancer of thyroid glands.
Cesium-137 brings about nervous, muscular and genetic changes.
Uranium causes skin cancers and tumors in the miners.
Actively growing and dividing cells like those of stratum germinativum, intestinal lining, bone marrow; gonads and embryo (with all cells rapidly growing and dividing) are more susceptible to ionising radiations.
A foetus in the womb may be killed by radiation which has little effect on the mother. Cancer cells are destroyed by radiation as they are of actively growing type. It has been reported that the pine seedlings are destroyed by radiations whereas the trees flourish.
Less active and non-dividing cells like osteocytes of bones, muscles fibres and neurons are not easily damaged by radiation.

Multiple Choice Questions : 1 Mark

Question 1.
Pollution is an undesirable change in physical, chemical and biological properties of
(a) Air
(b) Soil
(c) Water
(d) All of these
Answer:
(d) All of these

Question 2.
An indicator of air pollution is
(a) Lichens
(b) Mosses
(c) Ferns
(d) Pines
Answer:
(a) Lichens

Question 3.
Which of the following is the chief source of air pollution?
(a) Automobiles
(b) Burning coal
(c) Industries
(d) All of these
Answer:
(d) All of these

Question 4.
Carbon dioxide, nitrates and phosphates are
(a) Producers
(b) Decomposers
(c) Biotic substances
(d) Abiotic substances
Answer:
(c) Biotic substances

Question 5.
The hazardous metal pollutant from automobiles which hampers haemoglobin formation is
(a) NO₂
(b) SO₂
(c) Lead
(d) Mercury
Answer:
(c) Lead

Question 6.
Which of the following is an important atmospheric pollutant?
(a) Carbon monoxide
(b) Carbon dioxide
(c) Sulphur dioxide
(d) Hydrocarbon
Answer:
(a) Carbon monoxide

Question 7.
Which of the following is the least harmful pollutant?
(a) CO
(b) SO₂
(c) NO₂
(d) CO₂
Answer:
(d) CO₂

Question 8.
The presence of ozone (O₃) in the atmosphere of our earth
(a) Helps in checking the penetration of ultra-violet rays on the earth
(b) Is advantageous since it supplies O₂ for people travelling in jets
(c) Hinders higher rate of photosynthesis
(d) Both (b) and (c)
Answer:
(a) Helps in checking the penetration of ultra-violet rays on the earth

Question 9.
If BOD of a river is high, it means the river
(a) Is not polluted
(b) Is very polluted
(c) Does not have green plants
(d) Gets least amount of light
Answer:
(b) Is very polluted

Question 10.
The disease which is not caused by polluted water is
(a) Dysentery
(b) Jaundice
(c) Tuberculosis
(d) Typhoid
Answer:
(d) Typhoid

Question 11.
Which of the following is the index of pollution in a polluted lake?
(a) Algae
(b) Daphnia
(c) Frog
(d) Aquatic weeds
Answer:
(b) Daphnia

Question 12.
A powerful eye irritant present in smog is
(a) Nitric acid
(b) Peroxyacetyl nitrate
(c) Sulphur dioxide
(d) Ozone
Answer:
(b) Peroxyacetyl nitrate

Question 13.
The atmosphere pollutant which is not produced by the exhaust of motor vehicle in Delhi is
(a) Carbon monoxide
(b) Sulphur dioxide
(c) Flyash
(d) Hydrocarbon gases
Answer:
(c) Flyash

Question 14.
In Bombay, the major air pollutant is
(a) Carbon monoxide
(b) Hydrocarbons
(c) Algal spores
(d) All of these
Answer:
(a) Carbon monoxide

Question 15.
The most polluted city in the world is
(a) Tokyo
(b) New York
(c) Calcutta
(d) Mexico
Answer:
(d) Mexico

Question 16.
Which one is the major source of pollution in metropolitan cities?
(a) Pesticides
(b) Automobiles
(c) Industries
(d) Radioactive substances
Answer:
(c) Industries

Question 17.
The pollutant which directly affects the nervous system is
(a) DDT
(b) Aldrin
(c) Lindane
(d) Organic phosphate
Answer:
(d) Organic phosphate

Question 18.
Some effect of SO₂ and its transformation products on plants includes
(a) Plasmolysis
(b) Chlorophyll destruction
(c) Golgi body destruction
(d) All of these
Answer:
(b) Chlorophyll destruction

Question 19.
In the atmosphere, the accumulation of which gas does not lead to green house effect?
(a) N₂
(b) NO₂
(c) CO
(d) All of these
Answer:
(d) All of these

Question 20.
The environmental planning organisation is
(a) ICAR
(b) NEERI
(c) NCL
(d) NPO
Answer:
(b) NEERI

Question 21.
Contamination of radioactive materials are dangerous because it causes
(a) Biological magnification
(b) Gene mutation
(c) Photochemical smog
(d) Ozone destruction
Answer:
(b) Gene mutation

Question 22.
Which of the following is not an ionising radiation ?
(a) Alpha rays
(b) Beta rays
(c) UV rays
(d) Infrared
Answer:
(d) Infrared

Question 23.
The pollutant that is degradable but toxic to workers
(a) Melathion
(b) DDT
(c) Aldrin
(d) Lindane
Answer:
(a) Melathion

Question 24.
The Environment (Protection) Act to protect and improve the quality of environment (air, water and soil) was passed by the Government of India in the year
(a) 1971
(b) 1974
(c) 1981
(d) 1986
Answer:
(d) 1986

Question 25.
Which one of the following occurs in radioactive fallout and behaves like calcium in biogeochemical cycling of material in ecosystem?
(a) Strontium-30
(b) Cobalt-60
(c) Cesium-137
(d) None of these.
Answer:
(a) Strontium-30

Question 26.
Ozone prevents the entry of
(a) Infrared rays
(b) Visible rays
(c) UV rays
(d) X-rays
Answer:
(c) UV rays

Question 27.
Ozone layer of upper atmosphere is being destroyed by
(a) SO₂
(b) Chlorofluorocarbons (CFCs)
(c) CO₂
(d) Both (a) and (b)
Answer:
(b) Chlorofluorocarbons (CFCs)

Question 28.
Green muffler is used against which type of pollution?
(a) Air
(b) Soil
(c) Water
(d) Noise
Answer:
(d) Noise

Question 29.
Ozone hole refers to
(a) Reduction in the thickness of ozone layer in stratosphere
(b) Reduction in ozone layer in stratosphere
(c) Hole in the ozone layer
(d) Increased concentration of ozone
Answer:
(a) Reduction in the thickness of ozone layer in stratosphere

Question 30.
UV-B radiation from sun causes which of the following disorder of eyes?
(a) Cataract
(b) Glaucoma
(c) Dilation of pupil
(d) Some defect in retina
Answer:
(a) Cataract

Question 31.
Sound above is termed as noise
(a) 95 dB
(b) 80 dB
(c) 115 dB
(d) 140 dB
Answer:
(b) 80 dB

Question 32.
Flyash is a
(a) Mining waste
(b) Hospital waste
(c) Industrial waste
(d) Municipal waste
Answer:
(c) Industrial waste

Question 33.
Green house effect is warming due to
(a) Infrared rays reaching earth
(b) Moisture layer in atmosphere
(c) Increase in temperature due to increase in carbon dioxide concentration of atmosphere
(d) Ozone layer of atmosphere.
Answer:
(c) Increase in temperature due to increase in carbon dioxide concentration of atmosphere

Question 34.
ODS means
(a) Ozone developing substances
(b) Ozone depleting substances
(c) Ozone data source
(d) Office data secrecy
Answer:
(b) Ozone depleting substances

Question 35.
Montreal Protocol was signed in
(a) 1978
(b) 1987
(c) 1991
(d) 1993
Answer:
(b) 1987

Question 36.
Kyoto conference is connected with
(a) Limiting production of CO₂
(b) Developing alternatives to ODS
(c) Both (a) and (b)
(d) Reduction in use of energy
Answer:
(c) Both (a) and (b)

Question 37.
CFCs split up in stratosphere to release chlorine by the action of
(a) UV-A
(b) UV-B
(c) UV-C
(d) All of these.
Answer:
(c) UV-C

Question 38.
Thermal pollution causes
(a) Increase in metabolic activities of aquatic organisms
(b) Decreases in DO contents of water
(c) Oxygenation in water
(d) Both (a) and (b)
Answer:
(d) Both (a) and (b)

Question 39.
Greenhouse gases are
(a) Absorbers of long-wave heat radiations from earth
(b) Transparent to both solar radiations and long-wave radiations from earth
(c) Absorbers of solar radiations for warming the atmosphere of earth
(d) Transparent to emissions from earth for passage into outer space.
Answer:
(a) Absorbers of long-wave heat radiations from earth

Question 40.
Climate of the world is threatened by
(a) Increasing concentration of atmospheric oxygen
(b) Decreasing amount of atmospheric oxygen
(c) Increasing amount of atmospheric carbon dioxide
(d) Decreasing amount of atmospheric carbon dioxide.
Answer:
(c) Increasing amount of atmospheric carbon dioxide

Question 41.
The first effect of noise is
(a) Constriction of blood vessels
(b) Anxiety and stress reactions
(c) Increased heart beat
(d) Digestive spasm
Answer:
(b) Anxiety and stress reactions

Question 42.
Ban of DOT and start of Ganga action plan occurred in the year
(a) 1982 and 1985
(b) 1985 and 1986
(c) both in 1982
(d) both in 1985
Answer:
(b) 1985 and 1986

Question 43.
World environment day is
(a) 5th June
(b) 14th November
(c) 2nd October
(d) 28th February
Answer:
(a) 5th June

Question 44.
The worst environmental hazards created accidents in nuclear power plant and MIC gas tragedy respectively in
(a) Russia in 1990 and Bhopal in 1996
(b) Ukrain in 1986 and Bhopal in 1984
(c) Bhopal in 1994 and Russia in 1999
(d) Ukrain in 1988 and USA in 1984
Answer:
(b) Ukrain in 1986 and Bhopal in 1984

Question 45.
The ‘Earth Summit’ was held at
(a) Geneva
(b) New Delhi
(c) Sydney
(d) Rio-de-janeiro
Answer:
(d) Rio-de-janeiro

Fill in the blanks with suitable words

1. The agents that pollute the environment are called _______
2. ______ percent of atmospheric pollution is caused due to activities of modern man.
3. ______ pollutants may be solid or liquid particles.
4. Pollutants are evaluated on the basis of the amount and their relative _______
5. Ozone and nitrous compounds are _______ pollutants.
6. Oxidation of sulphur in the fossil fuels produces harmful gases ______ and _____
7. Particulate pollutants are produced as result of incomplete combustion of hydrocarbons and are ______
8. _______ serve as pollution indicators.
9. ________ is an agent or factor that causes cancer.
10. ________ are the chemicals that are released in the air with a force in the form
of mist or vapour.
11. The process of polluting streams, rivers and lakes by excessive addition of organic fertilizers is known as ________
12. ______ pollution is caused by the discharge of hot water from cooling towers of power plants.
13. _______ is a physical phenomena in which energy travels through the space.
14. ______ is the lung disease caused due to inhalation of gritty dust.
15. Threshold is the _______ is a physical phenomena in which energy travels through the space. is the lung disease caused due to inhalation of gritty dust. intensity at which a sound becomes perceptible.
Answer:
1. pollutants
2. 0.05
3. particulate
4. toxicity
5. secondary
6. SO₂, SO₃
7. carcinogenic
8. Lichens
9. carcinogen
10. aerosols
11. eutrophication
12. thermal
13. radiation
14. silicosis
15. lowest

State whether the following statements are True or False. If False, then write the correct statement.

Question 1.
Atmospheric pollution is caused due to addition of harmful substances from uncontrollable non-human sources.
Answer:
True.

Question 2.
Pollutants resulting from human activities are mainly discharged in remote and isolated areas.
Answer:
False. Pollutants resulting from human activities are mainly discharged in cities and industrial centres.

Question 3.
Vapours of compounds whose boiling point is below 200° C are classified as gaseous pollutants.
Answer:
True.

Question 4.
Lung diseases are more common in rural areas because of more air pollution.
Answer:
False. Lung diseases are more common in urban areas because of more air pollution.

Question 5.
Vapours of compounds whose boiling point is below 200° C are known as particulate.
Answer:
False. They are known as gaseous.

Question 6.
Products of atmospheric reactions of hydrocarbons and nitrogen oxides in the presence of sunlight are called secondary pollutants.
Answer:
True.

Question 7.
Atmospheric diffusion of air is maximum at elevations of 3000m above the earth’s surface.
Answer:
False. It is minimum at this altitude.

Question 8.
Dust and mist consist of particles smaller than one micrometre.
Answer:
False. They consist of particles larger than one micrometer.

Question 9.
Lead is poisonous because it hampers haemoglobin formation.
Answer:
True.

Question 10.
Nitrogen oxide impairs the functioning of lungs by causing accumulation of water in the air spaces.
Answer:
True.

Question 11 .
Ethylene gas bleaches and damages plant-leaves.
Answer:
False. Ethylene causes premature failing of leaves.

Question 12.
Abundant growth of lichens indicates pollution free air.
Answer:
True.

Detailed explanations in West Bengal Board Class 10 Life Science Book Solutions Chapter 5A Nitrogen Cycle offer valuable context and analysis.

WBBSE Class 10 Life Science Chapter 5A Question Answer – Nitrogen Cycle

Short Answer Type Questions : 2 Marks

Question 1.
What is the most abundant form under which nitrogen is found in nature?
Answer:
The most abundant nitrogen-containing molecule found in nature is molecular nitrogen (N₂). The air is 80% constituted of molecular nitrogen.

Question 2.
Under which form is nitrogen fixed by living beings?
Answer:
Most living beings cannot use molecular nitrogen to obtain nitrogen atoms: Producers fix nitrogen mainly from nitrate (N\(\mathbf{O}_3^{-}\)). Some plants also fix nitrogen from ammonia. Consumers and decomposers acquire nitrogen through digestion of mainly proteins and nucleic acids from the body of other living beings.

Question 3.
Why is leguminous crop rotation used in agriculture?
Answer:
Leguminous crop rotation and other types of crop rotation are used in agriculture because many bacteria important for the nitrogen cycle live in these plants. Leguminous crop rotation (or conjointly with the main crop) helps the soil to become rich in nitrates, which are then absorbed by the plants. Green manure, the covering of the soil with grass and leguminous plants, is also a way to improve the fixation of nitrogen and is an option for avoiding chemical fèrtilizers.

Question 4.
Define biological nitrogen fixation.
Answer:
The synthesis of organic nitrogenous compounds from atmospheric nitrogen by certain micro-organisms is called biological nitrogen fixation.

Question 5.
Why do plants need fixation of atmospheric nitrogen?
Answer:
Higher plants cannot directly utilize molecular nitrogen of the atmosphere. But certain micro-organisms can utilize atmospheric nitrogen. There are two types of nitrogen fixing micro-organisms: Asymbiotic and symbiotic.

Question 6.
What is the role of lichens in biological nitrogen fixation?
Answer:
Nostoc and Scytonema develop symbiotic association with fungi. This association is called lichens. The algal components fix the molecular nitrogen in the form of organic compounds.

Question 7.
What is the role of fungi in biological nitrogen fixation?
Answer:
Several species of Actinomycetes develop mycorrhizal association with the root of Casurina, Pinus and other plants. These mycorrhizae may be ectotropic and endotropic mycorrhizae. These fungi have ability to fix atmospheric nitrogen.

Question 8.
What is leghaemoglobin?
Answer:
The nodule is pink in colour. The pink colour is due to the presence of pigment leghaemoglobin. This pigment is synthesized by the host cells in response to bacterial infection. It is similar to haemoglobin of red blood cells of mammals.

Question 9.
Which intermediate compound is formed during biological nitrogen fixation?
Answer:
Diamide (NH=NH) and hydrazine (NH₂-NH₂) and NH₃-NH₃ are the intermediate compounds.

Question 10.
Define the following terms :
Answer:
Nitrogen fixation: The synthesis of organic nitrogenous compounds from atmospheric nitrogen by certain micro-organisms is called biological nitrogen fixation.
Asymbiotic organism : The free living nitrogen fixing organisms are called are asymbiotic organisms.
Leghaemoglobin : The nodule is pink in colour. The pink colour is due to the presence of pigment leghaemoglobin.

Long Answer Type Questions : 5 Marks

Question 1.
Describe nitrogen cycle briefly.
Answer:
The process by which limited amount of nitrogen is circulated and re-circulated throughout the world of living organisms is known as the nitrogen cycle. The chief reservoir of nitrogen is the atmosphere. Nitrogen makes up 78 per cent of the gases in atmosphere. Most living things cannot use atmospheric nitrogen. They cannot make amino acid and other nitrogen containing compounds from this nitrogen. They are dependent on nitrogen present in soil minerals. The shortage of nitrogen in the soil is the major limiting factor in plant growth. The living organism obtains nitrogen by two methods: Nitrogen fixation and decomposition.

(a) Nitrogen fixation : There are different methods to fix atmospheric nitrogen
i. Asymbiotic nitrogen fixation : The free living nitrogen fixing organisms are called asymbiotic organisms. There are following organisms which fix the atmospheric nitrogen: bacteria, anaerobic bacteria, blue green algae (cyanobacteria) and lichens. The example of anaerobic bacteria is Clostridium and the example of aerobic bacteria is Azotobacter. The example of blue green algae is anabaena.

ii. Symbiotic Nitrogen Fixation : It is the most important method of nitrogen fixation. These are of two types : Fungi (Actinomycetes) and Nodule forming Rhizobium species. Some fungi develop mycorrhizal association and fix atmospheric nitrogen. Similarly, some bacteria live in the nodule of the leguminous plants like bean, pea and gram. They fix atmospheric nitrogen.

iii. Nitrogen fixation by Electrification : The lightening of the thunder storm fixes the atmospheric nitrogen. Nitrogen and oxygen of the atmosphere combine with, each other during lightning. They form nitric oxide. It combines with more oxygen to form nitrogen peroxide. It is changed into nitric acid. Nitric acid reacts with alkalies of soil and form nitrates. These nitrates are used by the plants.

(b) Release of nitrogen by decomposition : Nitrogen is present in also present in dead plants and animals. Bacteria and fungi decompose these dead plants and animals and form nitrates and ammonia. These compounds are used up by plants. It has following steps:

i. Ammonification : The breakdown of nitrogenous compound like protein, amino acids into ammonia with the help of micro-organism like fungi and bacteria is called ammonification. Soil contains many organic materials in the form of complex organic compounds like protein, amino acids, nucleic acid and nucleotides. Most of the nitrogen formed in the soil by the decomposition of these organic compounds. Bacteria and fungi decompose these nitrogenous compounds into simple compounds. These microorganisms use the proteins and amino acids and release excess of ammonia (NH₃) or ammonium ions (NH\(\mathbf{O}_4^{+}\)). This process is known as ammonification.

ii. Nitrification : Several bacteria in soil oxidize ammonia or ammonium ions into nitrates. This oxidation is known as nitrification.

iii. Assimilation : The absorption and utilization of ammonia or nitrates by the plant is called assimilation. The plants can utilize ammonium directly. But most of the nitrogen moves from the soil into the roots in the form of nitrate. The nitrates are reduced back to ammonium in plant. This assimilation process requires energy. These ammonium ions finally transferred to carbon containing compounds. These compounds produce amino acids and other nitrogenous organic compounds.

(c) Loss of nitrogen : There are two sources of loss of nitrogen.
i. Leaching : Nitrates is soluble in water. So it is leached out of the soil by rain water. It is driven into the ground water streams, lakes and into the oceans. Some of it is utilized by algae. But some nitrogen is lost into the deep sediments and become part of the rock.

ii. Denitrification : The soil contains many denitrifying bacteria like pseudomonas, which break the nitrates and release the gaseous nitrogen into atmosphere. This process is known as denitrification.

Question 2.
Draw the word diagram of N₂ cycle.
Answer:

Question 3.
Distinguish the following terms :
Answer:

Multiple choice questions : 1 Mark

Question 1.
The conversion of nitrogen to ammonia or nitrogenous compounds is called as
(a) Nitrogen assimilation
(b) Nitrogen fixation
(c) Denitrification
(d) Nitrification
Answer:
(b) Nitrogen fixation

Question 2.
Plants absorbs N₂ in the form of
(a) nitrites (N\(\mathbf{O}_2^{-}\))
(b) nitrates (N\(\mathbf{O}_3^{-}\))
(c) ammonium (N\(\mathbf{H}_4^{+}\))
(d) all of these
Answer:
(d) all of these

Question 3.
Plants cannot absorb molecular N₂ in the atmosphere because
(a) N₂ has double bonds making it highly stable
(b) Abundance in the atmosphere inhibits absorption
(c) N₂ has triple bonds making it highly stable
(d) None of these
Answer:
(c) N₂ has triple bonds making it highly stable

Question 4.
Symbiotic N₂ fixing cyanobacteria are present in all except
(a) Anthoceros
(b) Azolla
(c) Cycas
(d) Gnetum
Answer:
(d) Gnetum

Question 5.
All the following are free living N₂ fixers except
(a) Rhizobium
(b) Azotobacter
(c) Rhodospirillum
(d) Clostridium
Answer:
(a) Rhizobium

Question 6.
Which of the following N₂ fixer is involved in symbiotic association with legumes forming root nodules?
(a) Rhizobium
(b) Azotobacter
(c) Rhodospirillum
(d) Clostridium
Answer:
(a) Rhizobium

Question 7.
Anabaena, a N₂-fixer is present in the root pockets of
(a) Marselia
(b) Salvinia
(c) Pistia
(d) Azolla
Answer:
(d) Azolla

Question 8.
Splitting of dinitrogen molecule into free nitrogen atom in biological N₂ fixation is carried out by
(a) hydrogenase
(b) nitrogenase
(c) dinitrogenase
(d) nitrate reductase
Answer:
(b) nitrogenase

Question 9.
The conversion of amino acids to ammonium by soil decomposers is called
(a) ammonification
(b) mineralization
(c) deamination
(d) Both a and b
Answer:
(d) Both a and b

Question 10.
Industrial fixation is accomplished by
(a) Helmonts process
(b) Haber process
(c) Friedel Crafts reaction
(d) Reimer Tiemann Reaction
Answer:
(b) Haber process

Question 11.
To fix one molecule of nitrogen
(a) 6 ATP molecules are required
(b) 12 ATP molecules are required
(c) 16 ATP molecules are required
(d) 20 ATP molecules are required
Answer:
(c) 16 ATP molecules are required

Question 12.
The root nodules of legumes contain a pink pigment which has high affinity for oxygen is
(a) nitric oxide (NO) haemoglobin
(b) leghaemoglobin
(c) haemoglobin
(d) bacterial haemoglobin
Answer:
(b) leghaemoglobin

Question 13.
Conversion of N\(\mathbf{O}_2^{-}\)to N\(\mathbf{O}_3^{-}\)is carried out by
(a) Nitrosomonas
(b) Nitrososcoccus
(c) Nitrobacter
(d) Clostridium
Answer:
(c) Nitrobacter

Question 14.
The process of conversion of soil \(\mathbf{O}_3^{-}\)to N₂ is called
(a) nitrification
(b) denitrification
(c) ammonification
(d) nitrogen fixation
Answer:
(b) denitrification

Question 15.
Leghaemoglobin creates
(a) Anaerobic condition for optimum activity of nitrogenase
(b) Aerobic condition for optimum activity of nitrogenase
(c) Required oxygen concentration for optimum activity of nitrogenase
(d) Suitable environment for nodule formation
Answer:
(a) Anaerobic condition for optimum activity of nitrogenase

Question 16.
Which of the followings is an anaerobic bacterium?
(a) Azotobacter
(b) Nitrobacter
(c) Clostridium
(d) None of these
Answer:
(c) Clostridium

Question 17.
Which of the followings is non-aerobic bacterium?
(a) Azotobacter
(b) Nitrobacter
(c) Clostridium
(d) None of these
Answer:
(a) Azotobacter

Question 18.
Which of the followings fixed nitrogen in waterlogged soil?
(a) Nostoc
(b) Nitrobacter
(c) Clostridium
(d) None of these
Answer:
(a) Nostoc

Question 19.
Which of the followings is a group of biological nitrogen fixing fungi?
(a) Nostacles
(b) Actinomycetes
(c) Casurina
(d) None of these
Answer:
(b) Actinomycetes

Question 20.
The nodule forming bacteria are:
(a) Azotobacter
(b) Nitrobacter
(c) Clostridium
(d) Rhizobium
Answer:
(c) Clostridium

Very Short Answer Type Questions : 1 Mark

Question 1.
Name the acids form through Natural process in N₂ cycle.
Answer:
Nitric acid, Nitrogen acid.

Question 2.
Name one bacterium which can fix N₂ symbiotically.
Answer:
Rhizobium bacterium.

Question 3.
Name one aerobic bacteria which can fix N₂.
Answer:
Azotobacter.

Question 4.
Name one anaerobic bacteria which can fix N₂.
Answer:
Clostridium.

Question 5.
Name one ammonifying bacterium.
Answer:
Bacillus mycoides.

Question 6.
Write two effects of N₂ cycle on human.
Answer:
(i) Nutrient cycle
(ii) Algal bloom in acquatic region.

Question 7.
_______ is the suspended liquid particle.
Answer:
Aerosol.

Fill in the blanks :

Question 8.
The free living nitrogen fixing organisms are called _ organisms.
Answer: asymbiotic

Question 9.
Several species of develop mycorrhizal association with the root of Casurina, Pinus and other plants.
Answer:
actinomycetes

Question 10.
Name the N₂ fixing organisms which have intermediate compounds
(a) NH=NH,
(b) NH₂-NH₂
Answer:
(a) asymbiotic
(b) actinomycetes.