WBBSE Class 7 Science Solutions Chapter 8 Environment and Public Health

Detailed explanations in West Bengal Board Class 7 Science Book Solutions Chapter 8 Environment and Public Health offer valuable context and analysis.

WBBSE Class 7 Science Chapter 8 Question Answer – Environment and Public Health

(Page no. 256)

1. Which instrument do we use to measure temperature?
Answer:
thermometer.

2. Which kind of street lamps are now being used instead of electric bulbs and tube lights?
Answer:
Fluroscent bulb

3. A special kind of metal, liquid in nature is used to make thermometer and fluroscent bulb. Name it.
Answer:
mercury.

4. Now, let us find out the other sources from which mercury can enter the human body.
Answer:

• mirror
• light
• vegetables
• water.

(Page no. 257)

1. Now, let us find out the other sources through which Arsenic and Fluoride can enter our bodies.
Answer:

• water
• pesticide
• food crops.

2. Write the effects of X-ray on different organs of human below.
Answer:

• Oesophagous – Tendency of vomiting, Diarrhoea
• Lung-Breathing trouble.
• Bone marrow-Improper formation of blood cell. Haemorrhage, Cancer.

(Page no. 260)

Besides many other physical factors increase the risks and cause many diseases. Discuss with your friends or teacher and complete the chart.
Answer:

Physical factors causing disease in the professional field	Symptoms/disease
1. Electricity	Shock, Heart problem, Nerve disorder.
2. Heat	Burn, boils, injury
3. Cold	Frost bite, fever, cough and sneezing
4. Sound	Deafness, Headache.
5. Radioactive element	Anaemia, Cancer, skin disease.

B. 1. Compounds of which metal did ancient Egyptians used to colour their potteries? (Iron/ Copper/Zinc) Copper.
2. Which gas can cause death in closed mine? (Hydrogen/Oxygen Carbon monoxide) Carbon- mono-oxide.
3. Which chemicals are used in colouring cosmetic cotton and toilet articles? (water/ Sodium chloride/Synthtic organic dies) Synthetic organic dies.
4. Which metal or metallic compounds are used in wall paints, making toys or making batteries? (Iron, Sodium, Lead) Lead.
We came to know about many components of chemical environments from the above discussion.

As per chemical nature these are-

Chemical Nature	Name of the component
1. Gas	Carbon-di-oxide, Carbon monoxide, Sulphurdioxide.
2. Metal	Mercury, Flouride.
3. Synthetic compound              ‘	Organic dies, chemicals.

Now discuss with your friends/teachers/doctors what diseases may occur in being engaged in above mentioned professions.

• Diabetes
• High blood pressure
• Pain in neck
• Insomnia
• Sugar
• Arthritis.

(Page no. 262)

Try to write down the diseases on problem related to the following professions :
Answer:

Professions	Related diseases/problems
1. Those who pick up tea leaf	decay of fingertips
2. Those who are traffic police.	breathing problem, poor eyesight, restlessness.
3. Those who are carpenter.	breathing problem, muscle cramp
4. Those who carry goods	pain in neck, anaemia
5. Rickshaw-puller	Arthritis, muscle cramp
6. Those who cook in front of oven	ache in eye, breathing problem, diz ziness
7. Those who work in cotton factory	breathing problem, anaemia
8. Those who are hospital worker	dizziness, vomiting tendency
9. Those who are worker in mines	breathing problem, dizziness, wound in skin
10. Those who are worker in construction industries.	Arthritis, cancer, wound in skin, muscle cramp, brittle bone
11. Those who work in laboratories.	ache in eye, poor eye sight, vomiting tendency, less or more hunger
12. Those who works in different factories	deafness, restlessness, cancer, heat cramp
13. Those who work in Jute factories	faint, anaemia
14. Those who are hawker	heat cramp, varicose vein of legs, less or more hunger

(Page no. 273)

Which of the following picture will you choose to control your anger and why ?

Listening Music, Do exercise, singing, Reading Books, Playing, Face to Face talking, Dancing with Music, Watering in the garden, Meditation or Yoga.

Way out of controlling anger	Why did you choose this method
Reading books.	It gives pleasure and calms down our mind.
Meditation or Yoga.	relieves mental tension and increases concentration.
Dancing with Music.	It gives joy and relieves tension.
Playing.	Increases concentration, calms mind.
Watering in the garden.	It gives pleasure and increases love for nature

(Page no. 274)

Name of the disease	How it spreads
1. Common cold	1. By air
2. Dysentery	2. By water
3. Malaria	3. By mosquito
4. Plague	4. By rats
5. Rabies, Hydrophobia	5. By dogs.

(Page no. 275)

Can you tell me how diseases spread through air? Let us write how common cold spreads.

How does common cold spread?	What precautions should a person suffering from common cold take so that the disease does not spread?
1. By sneezing	1. We should use handkerchief while sneezing.
2. By spitting or coughing	2. We should not spit or cough in front of any person.
3. Talking with affected person	3. We should keep distance or cover our mouth while talking
4. By air	4. We should not move freely in pub­lic places.

(Page no. 277)

Now discuss with your friends. Try to find out who among you suffer from the same problems.

Cause behind the problem.	Nature of the problem	How did you get rid of the problem
I. Eating eggs	rashes in body, sneezing, vomitting	take medicine
2. Dust entering the nose.	burning sensation in eyes and nose sneezing, water comes out from nose.	use handkerchief
3. Eating Prawn.	red rashes, itching sensation	take medicine
4. Inhaling pollen of flower.	sneezing, burning sensation in nose.

Measures to prevent air-borne diseases :

• When ill, at the time of sneezing/ coughing cover your mouth and nose with a handkerchief.
• Do not spit here and there.
• Do not come in close contact with affected person.

(Page no. 278)

Fill up the following table after bearing about some other air borne diseases.

(Page no. 285)

Fill up the following table after barning about some water-borne disease.

(Page no. 288)

Try to write the name of some other disease which are spread by animals.

Name of the disease	The organism that spreads the disease
1. Malaria 2.  Dengue 3.  Typhoid 4.  Plague 5. Cholera 6.  Yellow Fever 7.  Rabies 8.  Filaria (Elephantiasis)	bite of female Anopheles mosquito bite of Aedes aegypti mosquito, rod-shaped bacteria Salmonella Typhi bite of rat fliesAedes mosquito biting of dogs and foxes small worm Wuchereria

Class 7 Science Chapter 8 Question Answer West Bengal Board – Environment and Public Health

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

Question 1.
Which one of the following in water-borne disease?
i) Diabetes
ii) Cholera
iii) Allergy
iv) Scurvy
Answer:
ii) Cholera.

Question 2.
Which of the following disease has been eradicated?
i) Small Pox
ii) Plague
iii) Polomyelities
iv) Kala-zar
Answer
i) Small-Pox

Question 3.
Well known effective drug for Malaria is ………….
i) Penicilin
ii) Paracitamol
iii) Quinine
iv) Cough syrup
Answer:
iii) Quinine.

Question 4.
A viral disease is …………..
i) Cancer
ii) Leukaemia
iii) Typhoid
iv) Yellow fever
Answer:
iv) Yellow fever

Question 5.
Dehydration results from …………..
i) Pneumonia
ii) Measles
iii) Rabies
iv) Cholera
Answer:
iv) Cholera.

Question 6.
Name of the British army doctor who proved that Malaria is a mosquito-borne disease is ………
i) Louis Pasteur
ii) Ronald Ross
iii) Dr. Edward Jenner
iv) Joseph Lister
Answer:
ii) Ronald Ross

Question 7.
Aedes mosquito spreads ………
i) Dengue
ii) Typhoid
iii) Malaria
iv) Kala-zar
Answer:
i) Dengue

Question 8.
Which is a beneficial fungi?
i) Neurospora
ii) Claviceps
iii) Penicuilium
iv) Rhizopus
Answer:
iii) Penicillium.

Question 9.
A harmful chemical added to chowmin and chilly chicken to impart a meaty flavour is ……………….
i) Clove
ii) Turmeric
iii) Ajinomoto
iv) Chilly
Answer:
iii) Ajinomota

Question 10.
Which seed is mixed with mustard seed—
i) Poppy seed
ii) Rapeseed
iii) Gramseed
iv) Argemone seed
Answer:
iv) Argemone seed.

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

1. The…………. look after our mental health.
Answer:
psychologists.

2. The menance of …………. has been fully eradicated from the world by vaccination alone by the year 1977.
Answer:
small pox.

3. Tuberculosis is a …………. disease.
Answer:
communicable

4. The substances that cause allergy in our body are termed as ………….
Answer:
allergen.

5. …………. spreads from contaminated water.
Answer:
cholera.

6. Diseases which spread through water are termed as ………….
Answer:
water-borne diseases.

7. …………. is one type of malarial parasite.
Answer:
Plasmodium Vivax.

8. Mosquito is the …………. host and other vertebrate animals are the host.
Answer:
primary or definitive, secondary or intermediate.

9. …………. spread diseases like Typhoid and Diarrhoea.
Answer:
House fly.

10. Usually the …………. grow on food items rich in Carbohydrates.
Answer:
fungi.

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

1. Powdered khesari dal is mixed with besan because khesari dal is very cheap.
Answer:
true

2. Lathyrism has been observed in America.
Answer:
false

3. Argemone seeds are darker than mustard seeds.
Answer:
true

4. Coloured sweets and icecreams may contain colourants that can cause cancer.
Answer:
true

5. Various dyes used during Holi can cause problems of heart.
Answer:
false

6. Sometimes immediately after eating food items like prawn and brinjal uneasiness sets in the body.
Answer:
true

7. Poultry products, raw vegetables unpasteurized milk often contain harmful mi¬crobes.
Answer:
true

8. Usually the fungi grow on food items rich in fats.
Answer:
false

9. The mosquito is a mechanical vector.
Answer:
false

10. Spoilage of various types of food is due to the microbial degradation by various microorganisms.
Answer:
true

11. House flies spread Kala-azar.
Answer:
false

12. Legs of sand flies are long and thin.
Answer:
true

Match the column A with column B

Column A	Column B
a) Lathyrism has been observed	i) attacks the poultry birds
b) Some safe colours are now being	ii) may be present in food
c) A type of influenza virus	iii) made from flowers
d) Yeast is required for	iv) spread Malaria
e) Some very dangerous types of bacteria	v) make no sound while flying
f) Aedes mosquitoes	vi) in Ethiopia, Bangladesh and India
g) Anopheles mosquitoes	vii) spread dangue
h) Culex mosquitoes	viii) making bread

Answer:
a) Lathyrism has been observed in Ethiopia, Bangladesh and India.
b) Some safe colours are now being made from flowers.
c) A type of influenza virus attacks the poultry birds.
d) Yeast is required for making bread.
e) Some very dangerous types of bacteria may be present in food.
f) Aedes mosquitoes spread dangue.
g) Anopheles mosquitoes spread Malaria.
h) Culex mosquitoes make no sound while flying.

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

Question 1.
Name some chemical which can cause harm if they enter our body.
Answer:
Arsenic and Fluoride.

Question 2.
Define the term health.
Answer:
Health means physical, mental and social healthiness, it does not only mean fitness of body.

Question 3.
Mention some steps of prevention of disease.
Answer:
Vaccination, to add nutritious ingredients from outside (Iodine, iron, Vitamin)

Question 4.
Name some diseases which spread through air.
Answer:
Common cold, Cough, Flu, Chicken Pox, Scarlet fever, Diptheria etc.

Question 5.
Name some water-borne diseases.
Answer:
Cholera, Diarrhoea, Jaundice, Typhoid, Tuberculosis and Dysentery.

Question 6.
Name the organs mosquitoes use to drink blood.
Answer:
Labium, Mandible, Maxilla, Hypopharynx and Labrum.

Question 7.
What kind of mosquitoes spread Malaria?
Answer:
Anopheles mosquitoes spread Malaria.

Question 8.
What kind of mosquitoes spread Filaria?
Answer:
Culex mosquitoes spread Filaria.

Question 9.
What kind of mosquitoes spread Dengue?
Answer:
Aedes mosquitoes spread Dengue.

Question 10.
Mention an identifying feature of Asdes mosquitoes.
Answer:
While taking rest they sit almost paralleliy to the ground.

Question 11.
Mention an identifying feature of Anopheles mosquitoes.
Answer:
While taking rest they sit making an acute angle with the surface.

Question 12.
Mention an identifying feature of Culex mosquitoes.
Answer:
While taking rest they sit paralleliy as the surface.

Question 13.
Mention a symptom of Polio.
Answer:
Unnatural fatigue in the muscles of hands and legs.

Question 14.
What is the name of pathogen of Tuberculosis?
Answer:
Bacteria is the pathogen of Tuberculosis.

Question 15.
Write a measure to prevent airborn diseases.
Answer:
When ill, at the time of sneezing/coughing one must cover his mouth and nose with a handkerchief.

Question 16.
What is the name of pathogen of common cold.
Answer:
Virus is the pathogen of common cold.

Question 17.
When Cholera appeared in form of epidemic in bengal?
Answer:
In the year 1817 Cholera appeared in form of epidemic in bengal.

Question 18.
In what type of food items bacteria grow?
Answer:
Generally Bacteria grow in food items rich in protein (e.g. meat, egg, fish, dairy products)

Question 19.
In what type of food items fungi grow?
Answer:
Usually the fungi grow on food items rich in Carbohydrate.

Question 20.
Name some Bacterial Pathogen caused disease.
Answer:
Salmonellosis. Campylobacteriosis, Food-borne toxicity, Botlism.

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

Question 1.
How are fungi beneficial?
Answer:
Fungi is used to produce food like bread, cheese and alcoholic beverages. Some antibiotics are produced from fungi, penicilium and yeast is required for making bread.

Question 2.
Why House fly is called a Mechanical vector and mosquito a Biological Vector?
Answer:
House fly only does the work of carrying the germ, so it is called Mechanical Vector. On the other hand the mosquitoes allow the germ to breed inside their body, so the mosquito is a Biological Vector.

Question 3.
What are Parasites?
Answer:
Some worms infest various organs of animals. These worms are parasites. If we take raw or under cooked meat of such animals, the parasites enter our bodies causing many diseases.

Question 4.
What is Bird-flu? How it effects other birds and human beings?
Answer:
Often a type of influenza virus (H5N1) attacks the poultry birds, this is called Bird-flu. The saliva catarrhal discharge or excreta of affected birds can infect other birds too. If human beings come in contact with skin, excreta or blood of virus-infected chicken, they can catch the diseases.

Question 5.
How microbial contamination of food occurs?
Answer:
Poultry products (egg, milk), raw vegetables unpasteurized milk often contain harmful microbes. If these food items are not properly processed or if they are taken raw, various types of infections may arise.

Question 6.
What is Allergy?
Answer:
Our immune system sometimes reacts to different proteins or other substances present in food. Allergy is basically the response generated by our immune system towards foreign proteins. This may cause itching sensation, rashes on skin and uneasiness in the body.

Question 7.
what can happen if food items with harmful additives is taken for a long time?
Answer:
Prolonged use of food items containing such harmful additives can lead to serious problems of the degestive and nervous system. It can also cause kidney diseases and may even cause cancer.

Question 8.
What is radioactive substances?
Answer:
Some invisible rays are emited continuously from elements like uranium and plutonium and other compounds. These are called radioactive substances.

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

Question 1.
Mention some causes of mental problem.
Answer:

• Disorder by birth: malnutrition of foetus, various infection after birth prevents the growth of mind and intelligence of the child.
• Mental pressure: various violent activities, unexpected incidents some times causes mental pressure beyond tolrance.
• Many family problems.
• Conflict and being unable to take decision.
• Addiction.

Question 2.
What is the proboscis? Did it help in male mosquito in sucking blood? How it is used by the mosquito to spread diseases?
Answer:
Various mouth parts of a mosquito get transformed into a proboscis for their special food habit. The mosquito has a long tubes like proboscis. In case of female mosquitoes the proboscis is slender and pointed just like an injection needle. But the proboscis in a male mosquito is blunt, so they can suck only different plant juice like necter, juice of fruits etc.

At the time of sucking blood a female mosquito infuses to saliva into the body and that animal through proboscis. They do so for preventing the blood from getting coagulated while sucking. Through this saliva the germs from the blood of a female mosquito enter into the body of that animal.

Question 3.
Which mosquito spread Malaria? Write down its identifying features.
Answer:
Female Anopheles spread Maleria. Its identifying features are-

• Black spot on the wings.
• At the time of taking rest they sit making an acute angle with the surface
• Make sound while flying.
• Come out in the evening.
• Lay eggs in clean water.

Question 4.
Name the diseases spread by Sand Fly. How can you identify it?
Answer:
Sand Fly spreads Kala-zar and Sand Fly fever.

• Sand flies are smaller than mosquitoes in size.
• Body is very hairy.
• Legs are long and thin.
• Come out after dark.

Question 5.
Describe the identifying features of Culex Mosquito. Name the diseases Culex can spread ?
Answer:
Identifying features of Culex mosquitoes are

• No spot on the wings.
• Sit parallelly as the surface while taking rest.
• Make no sound while flying.
• Come out at night.
• Lay eggs in dirty water. Culex mostquitoes spread Filaria and Encephalitis.

Question 6.
Name the diseases Aedes mosquitoes spread. How can we identify them?
Answer:
Aedes mosquitoes spread Dengue and Chickungunia diseases. Each identifying features are —

• White and Black stripes on the abdomen and legs.
• While taking rest sit almost parallely to the ground.
• Make no sound while flying.
• They come out in day time.
• Lay eggs in clean water.

Question 7.
What are the identifying features of House Fly? Name the diseases they can spread.
Answer:
A House Fly has ……..

• Grey-coloured thorax.
• 4 long black stripes on the back.
• Whole body is covered with hair.
• They come out during day time and remain inactive at night. House Flies spread Typhoid and Diarrhoea.

Question 8.
Onchocerciasis disease is spread by a fly, name it and describe its features.
Answer:
Black Fly spreads on Onchocerciasis

• Black Fly is black in colour.
• Proboscis is small in size and like a toothed dagger.
• Body is stout
• Come out during day time in groups and are very active just before down and dusk.

Question 9.
How fly spreads diseases?
Answer:
The fly spreads diseases in three different manners.
(i) Whenever they sit on stool, urine, pus, spittle etc. then minute particles of those things get stuck to their legs and antennae. When this fly sits on food items, germs are mixed with those food stuff and infection occurs.

(ii) The fly can not take solid food. So they vomit on solid food. As a result, parts of the solid food gets liquified and the fly takes the food with the help of the proboscis. With that vomit the germs from the body of the fly get mixed with our food items and infection occurs.

(iii) House flies excrete throughout the whole day at the interval of five minutes wherever
they sit. Many germs are present in the stool of the fly. When they defecate on our food, these germs get mixed with our food.

Question 10.
Tell the difference in the ways of transmission of diseases by the flies and the mosquitoes
Answer:

Question 11.
Describe some resources to control mosquito.
Answer:

• Water in reservoirs, buckets, flower vases should be changed every 2-3 days.
• Fishes like (Guppy, Panchax, Shol, Lata, Gambusia etc.) should be allowed to grow in stagnants waters because they eat the larvae of mosquitoes.
• Kerosene, diesel, bleaching powder should be spiaiged in the drains.
• Mosquito killer spray or liquid water should be used inside house to keep it free from mosquitoes.

Question 12.
Why food stuff gets spoiled?
Answer:
Spoilage of various types of food is due to the microbial degradation of food by various micro organisms. These micro-organisms are generally bacteria and fungi. When the microbes present in a food grow, they degrade the food with their enzymes and absorb the simple compounds thus obtained into their cells.

Question 13.
Name some Bacteria which are beneficial.
Answer:
Lactobacillus Bacteria help to-make curd. We obtain many life saving drugs from several species of streptomyces Bacteria. Some special Bacteria residing in the stomach of cattle help them in digesting cellulose. Some intestinal Bacteria help human beings by producing the much-needed vitamin Bp.

Question 14.
What is pasteurization?
Answer:
In simple words, pasteurization is the process of destroying the pathogenic microbes along with to their spores in food, especially liquid food (mild and dairy products, fruit juice etc.) This method of making foods and beverage free from microbes was discovered by the french Louis Pasteur, so to honour him the method is named as Pasteurization.

Question 15.
What are the common symptoms of allergy from food?
Answer:

• Rashes on skin.
• Itching sensation all over the body.
• Swelling of lips, throat and tongue
• Uneasiness in throat respiratory problems.
• Redness in eye and face,
• Vomiting
• Abdominal cramp
• Diarrhoea.

Question 16.
When a food can be said to be adultered?
Answer:

• When something is added to food that lowers its nutritional value.
• When some cheap additive is mixed with food instead of some necessary ingredients.
• When some harmful additive is added to the food to make the food look more attractive and to bring desirable flavour.

Question 17.
What is ‘dropsy’? How dropsy affects us?
Answer:
Argemone seeds closely resemble mustard seeds are cheaper than mustard. The oil extracted from argemone seeds is deliberately mixed with mustard oil. Long term use of such idulterated mustard oil. cause a disease called ‘dropsy’. Dropsy severely damages skin and organs like liver, lungs, kidney and heart. It can even cause failure of heart and the lungs, leading to death.

Question 18.
What is Lathyrism?
Answer:
Often Khesari daal which is very cheap (seeds of Lalhyrus Sativus) mixed with Arhar daal. Continued intake of substantial amount of Khesari daal for 2-3 months can cause progressive spastic paralysis. This is Lathyrism.

Question 19.
How fungi can be beneficial?
Answer:
We take the help of fungi to produce food items like bread, cheese and alcoholic beverages. The affinity of fungi for carbohydrate-rich food help the fungi in making those food items and beverages. For example, some antibiotics are produced from the fungus penicillium yeast is required for making bread.