CBSE Class 10 Science Our Environment VBQs Set 04

This page has 20 value based and real-life questions with answers for CBSE Class 10 Science Chapter 13, Our Environment. The situations cover segregating waste, saying no to polythene and plastic, burning of garbage, kulhads and paper cups, the ozone layer, an eco-club, the decline of vultures and how a student can spread awareness at school and at home, and each answer also names the value shown.

Value Based Short Answer Questions

Question 1. Ayush went to a nearby park with his friends for a picnic. He saw that after picnic is over all his friends were throwing the leftover food, plates, cups, glasses here and there. He suggests them not to do like that and segregate the wastes and dispose them in red and green dustbins kept in park.
(i) Why do you think Ayush told his friends to segregate wastes and throw in separate dustbins?
(ii) How can we contribute in keeping parks, roads, sea beaches clean?
Answer:
(i) There are two types of waste. Biodegradable waste (leftover food, vegetable peels, paper plates) can be decomposed by microbes and made into compost. Non-biodegradable waste (plastic cups, glasses) is recycled or disposed of by other methods. Since the two kinds need different treatment, they should be kept in separate dustbins.
(ii) We should not litter, throw waste only in dustbins, separate biodegradable and non-biodegradable waste, organise awareness campaigns, and ask for dustbins to be placed in such public places.
Values shown: civic sense and responsibility towards the environment.
In simple words: Sort the waste, use the dustbin and keep public places clean.

Teacher's Note:
1. State the values at the end of every value based answer.
2. Green bins are for wet (biodegradable) waste and blue or red bins for dry waste.

Question 2. Meera saw that her friend Reema was carrying polythene bags for shopping. She immediately stopped her and told her not to carry polythene bags.
(i) Why Meera stopped her friend Reema to carry polythene bags for shopping?
(ii) What alternatives could be done to replace polythene bags?
Answer:
(i) Polythene is a polymer and is non-biodegradable. It accumulates in the soil and reduces its fertility, blocks drains and causes water logging, and if animals such as cows eat it, it can block their alimentary canal.
(ii) Polythene bags can be replaced with jute bags, cloth bags or paper bags.
Values shown: environmental awareness and the courage to correct a friend politely.
In simple words: Polythene does not rot and harms soil, drains and animals, so use cloth, jute or paper bags.

Teacher's Note:
1. Give at least two harmful effects of polythene.
2. Cloth and jute bags can be reused many times.

Question 3. While going to school and coming back from school Tarun watches that in a slum area they burn plastics which produce lot of gases.
(i) Is burning of plastic environmental friendly?
(ii) Suggest two alternatives for proper disposal of plastics?
Answer:
(i) No. Burning plastic releases harmful, toxic gases, some of which cause cancer and breathing problems, and it pollutes the air.
(ii) Plastics should be reused as many times as possible or recycled in recycling plants.
Values shown: concern for public health and the environment.
In simple words: Do not burn plastic; reuse or recycle it.

Teacher's Note:
1. Name the effect on air and on health.
2. Reduce, reuse and recycle are the better options.

Question 4. Rohan was watching television when his mother instructed him to empty the home garbage bin which had become full, into public garbage bin. Rohan emptied the home garbage bin in front of his house as the public garbage bin was little far off. His mother saw him doing so. She tried to explain him the problems associated with improper garbage disposal.
(a) Mention any 2 problems, society faces due to improper garbage disposal.
(b) Mention three values displayed by Rohan’s mother.
Answer:
(a) (1) Garbage dumped in the open produces foul smell and becomes a breeding place for flies and mosquitoes, which spread diseases such as cholera, typhoid and malaria. (2) It pollutes the soil and water, clogs drains and spoils the surroundings.
(b) Values shown by Rohan’s mother: environmental awareness, responsibility towards society, and the habit of guiding children with patience (teaching rather than scolding).
In simple words: Open garbage spreads disease and pollution; the mother showed awareness, responsibility and patience.

Teacher's Note:
1. Give two clear problems and three one-line values.
2. Values are about attitudes, not about the waste itself.

Question 5. After the examinations Rakesh with his friends went on a picnic to a nearby park. All friends carried cooked food packed in plastic bags or plastic cans. After eating the food some friends collected the leftover food and plastic bags etc., and planned to dispose them off by burning. Rakesh immediately checked them and suggested to segregate the leftover food and peels of fruits from the plastic materials and respectively dispose them off separately in the green and red dustbins placed in the corner of the park.
(a) In your opinion, is burning plastic an eco-friendly method of waste disposal? Why? State the advantage of method suggested by Rakesh.
(b) How can we contribute in maintaining the parks and roads neat and clean?
Answer:
(a) No, burning plastic is not eco-friendly. It produces toxic fumes and causes air pollution. Plastic is non-biodegradable, so it also cannot simply be dumped.
Advantage of Rakesh’s method: biodegradable waste (leftover food, fruit peels) can be turned into compost and plastic can be sent for recycling, so waste is handled safely and the environment stays clean.
(b) By not littering, using dustbins, segregating the waste, and spreading awareness among others.
Values shown by Rakesh: awareness, responsibility and leadership.
In simple words: Do not burn plastic; separate the waste so that each kind can be handled properly.

Teacher's Note:
1. Explain why burning is harmful, then the benefit of separate dustbins.
2. Add one line on values to score full marks.

Question 6. When the government banned the use of polybags in Delhi, the vegetable grocers found it difficult as it affected their sales. The market committee held a meeting and decided to spread awareness about harmful effect of polybags.
(i) How will you convince people that plastics are harmful to the environment?
(ii) What alternatives of polythene bags do we have, which are environment friendly?
(iii) Not many people in Delhi have stopped using polythene bags even though they are officially banned. How can schools inculcate environmental values in students?
Answer:
(i) Tell people that plastic is non-biodegradable and stays for hundreds of years, chokes drains, pollutes soil and is eaten by cows and other animals, which can kill them. Burning it gives toxic gases.
(ii) Paper bags, jute bags, cotton or cloth bags and bags made of other biodegradable materials. Carrying your own shopping bag is also more convenient.
(iii) Schools can teach students to protect the environment, run eco-clubs, make paper bags and give them to small shopkeepers regularly, and hold rallies and poster competitions so that habits change gradually.
In simple words: Explain the harm, offer cloth or paper bags, and teach children early.

Teacher's Note:
1. Back each point with a fact; do not only say plastic is bad.
2. Schools can change habits through activities.

Question 7. You have been selected to talk on “Ozone layer and its protection” in the school assembly on Environment Day.
(i) Why should ozone layer be protected to save the environment?
(ii) List any two ways that you would stress in your talk to bring in awareness among your fellow friends that would also help in protection of ozone layer as well as the environment.
Answer:
(i) The ozone layer in the stratosphere prevents the harmful ultraviolet rays of the Sun from reaching the Earth’s surface. Without it, UV rays would cause skin cancer, cataract and damage to the immune system, and would harm plants and aquatic life.
(ii) (1) Avoid using products that contain CFCs, such as old refrigerators and aerosol sprays, and ask for CFC-free products. (2) Reduce the use of vehicles and fluorescent lights and save energy.
Values shown: awareness and responsibility towards the environment.
In simple words: Protect the ozone layer because it shields us from UV; avoid CFC products.

Teacher's Note:
1. Say what the layer does, what happens without it and what we can do.
2. CFCs are used in refrigerators, air conditioners and aerosols.

Question 8. (a) Why is it necessary to conserve our environment? (b) State the importance of green and blue dustbins in the safe disposal of the household waste.
Answer:
(a) It is necessary to conserve the environment because it provides us food, air, water, shelter and many useful products; it protects the ozone layer, keeps food chains running and prevents damage to species.
(b) Household waste is collected in two bins. The green bin is for wet or biodegradable waste, which is composted, and the blue bin is for dry or non-biodegradable waste, which is recycled. This makes disposal easy and safe and supports the reduce, reuse and recycle approach.
In simple words: Conserve the environment because we live on it; use separate bins to dispose of waste safely.

Teacher's Note:
1. Give two reasons for part (a).
2. Say which bin is for which type of waste.

Question 9. Salman wants to volunteer for Swachh Bharat Abhiyan intership. He got a responsibility to device various methods for garbage management. Help him to write various ways to control and manage garbage.
Answer:
(1) Segregate waste at the source into biodegradable and non-biodegradable waste.
(2) Convert biodegradable waste (kitchen waste, leaves) into compost or biogas.
(3) Recycle paper, glass, metals and plastic, and reuse jars, bags and bottles.
(4) Dispose of hospital and hazardous waste by incineration, and dump the remaining waste in sanitary landfills.
(5) Reduce the use of disposable and single-use items, and carry cloth bags.
In simple words: Separate, compost, recycle, reuse and reduce.

Teacher's Note:
1. The 5 R’s are reduce, reuse, recycle, refuse and repurpose.
2. Write the methods as short numbered points.

Value Based Long Answer and Case Based Questions

Question 10. The activities of man had adverse effects on all forms of living organisms in the biosphere. Unlimited exploitation of nature by man disturbed the delicate ecological balance between the living and non-living components of the biosphere. The unfavourable conditions created by man threatened the survival not only of himself but also of the entire living organisms on the mother Earth. One of your classmates is an active member of ‘Eco-club’ of your school, which is creating environmental awareness amongst the school students, spreading the same in the society and also working hard for preventing environmental degradation of the surroundings.
(A) Why is it necessary to conserve our environment?
(B) State the importance of green and blue dustbins in the safe disposal of the household waste.
(C) List two values exhibited by your classmate who is an active member of the Eco-club of your school.
Answer:
(A) The ecosystem gives us food, shelter and the air we breathe, so we cannot live without it. Conserving it prevents damage to the environment and protects endangered species.
(B) Biodegradable waste goes into the green bin and non-biodegradable waste goes into the blue bin. Separate dumping makes composting and recycling possible and reduces pollution.
(C) The classmate shows concern for the environment and social responsibility / leadership by spreading awareness.
In simple words: We depend on the environment, so we must protect it and sort our waste.

Teacher's Note:
1. Values are qualities such as awareness, responsibility, leadership and cooperation.
2. Part (B) is the same as a common board question.

Question 11. Answer the following on the basis of the paragraph: India today is facing the problem of overuse of resources, contamination of water and soil and lack of methods of processing the waste. The time has come for the world to say goodbye to “single use plastics”. Steps must be undertaken to develop environment-friendly substitutes, effective plastics waste collection and methods of its disposal. Indore treated 15 lakhs metric tonnes of waste in just 3 years, through biomining and bioremediation techniques. Bioremediation involves introducing microbes into a landfill to naturally ‘break’ it down and biomining involves using trommel machines to sift through the waste to separate the ‘soil’ and the waste component.
(a) State two methods of effective plastic waste collection in your school.
(b) Name any two uses of ‘single use plastic’ in daily life.
(c) If we discontinue the use of plastic, how can an environment-friendly substitute be provided?
(d) Do you think microbes will work similarly in landfill sites as they work in the laboratory? Justify your answer.
Answer:
(a) (1) Keep separate dustbins for plastic waste. (2) Use reusable items in the canteen and at school events and encourage less plastic in packed lunches.
(b) Single use plastic is used for grocery bags, food packaging, bottles, straws, cups and cutlery (any two).
(c) Cloth, jute and paper bags, steel, glass or earthen containers and wooden utensils can replace plastic.
(d) Not exactly in the same way. In a laboratory the temperature, moisture and oxygen are controlled, but conditions in a landfill vary and the waste is mixed, so microbes work more slowly and need extra support such as added microbes and sorting of the waste.
Value: responsible use of resources.
In simple words: Plastic can be collected, replaced and treated, but a landfill is not as controlled as a laboratory.

Teacher's Note:
1. In a laboratory the conditions are controlled, but in a landfill they are not, so the microbes do not work in the same way.
2. Give clear, practical suggestions.

Question 12. Why is Government of India imposing a ban on the use of polythene bags? Suggest two alternatives to these bags and explain how this ban is likely to improve the environment.
Answer:
Polythene bags are non-biodegradable. Microbes cannot decompose them, so they persist in the environment for a long time, harm soil fertility, choke drains and cause water logging, which gives rise to mosquito breeding and diseases such as malaria and dengue.
Two alternatives: jute bags and cloth bags.
The ban will reduce solid waste, keep drains clear, protect animals and soil, and reduce pollution.
In simple words: The ban stops plastic waste that never rots, and cloth or jute bags replace it.

Teacher's Note:
1. Connect the ban to non-biodegradable waste.
2. Two alternatives are enough.

Question 13. Suppose you find a heap of domestic waste, in a nearby park, which is decomposing. What would you do to make the people of the surrounding area realise that such type of disposal of domestic waste is harmful to the environment?
Answer:
I would make people aware of the ill effects of waste by: (1) conducting seminars and talks about the negative effects of waste on the environment, (2) using pamphlets and posters to give information, and (3) forming an eco-club in the society.
I would tell them that improper disposal releases harmful gases, becomes a breeding place for mosquitoes and flies which spread malaria and dengue, can wash into water bodies with rain water and harm aquatic life, and its chemicals can contaminate the soil.
Values shown: civic responsibility and leadership.
In simple words: Educate people through talks and posters and show them the harm of open dumping.

Teacher's Note:
1. Give at least two ways to create awareness.
2. Name two harmful effects of open dumping.

Question 14. Rita wants to have an aquarium at home. What are the things that she needs to keep in mind in designing an aquarium?
Answer:
The fish need free space for swimming, water, oxygen and food. So Rita needs a good aquarium tank, an oxygen pump (aerator) to supply oxygen, and fish food from the market.
Aquatic plants (producers) and pebbles should be added, and algae eating fish can help keep the tank clean.
An aquarium is an artificial ecosystem without natural decomposers, so about a quarter of the water should be changed regularly and overcrowding should be avoided, because it lowers oxygen and increases waste.
In simple words: An aquarium needs oxygen, food, plants and regular cleaning because it is not a complete ecosystem.

Teacher's Note:
1. Link the answer to the fact that an aquarium is an artificial ecosystem.
2. Mention at least three items needed.

Question 15. ‘Number of vultures are decreasing remarkably now-a-days, which is a matter of concern’. Answer the following questions related to the above given statement.
(i) Vultures belong to which category of animals?
(ii) What is their role in nature to maintain ecological balance?
(iii) At which trophic level, will you place vultures in a food chain?
(iv) How much energy is passed on at each trophic level in a food chain? Give the energy flow diagram of an ecosystem.
(v) Mention one of the main cause for this decline in the number of vultures.
Answer:
(i) Vultures are scavengers, a kind of carnivore that feeds on dead animals.
(ii) They clean up dead animals, which prevents the spread of diseases and keeps the environment clean, so they help to maintain the ecological balance.
(iii) They feed on the flesh of animals, so they are placed at a high trophic level, usually the third or fourth.
(iv) About 10% of the energy passes to the next trophic level: Sun → Producers (1000 J) → Herbivores (100 J) → Carnivores (10 J) → Vultures (1 J).
(v) A main cause is poisoning by the veterinary drug diclofenac, which enters their bodies when they eat the carcasses of treated cattle (loss of habitat is another cause).
In simple words: Vultures clean up dead animals; losing them harms the balance of nature.

Teacher's Note:
1. Take the energy figures only as an example; the rule is 10% to the next level.
2. Scavengers act as natural cleaners.

Question 16. What are the advantages of paper bags over plastic bags during shopping?
Answer:
(1) They are made of biodegradable material.
(2) They do not cause environmental pollution.
(3) They can be recycled and reused.
(4) They are strong and can carry a good load.
So paper bags are the better choice for shopping.
In simple words: Paper bags rot, can be recycled and do not pollute.

Teacher's Note:
1. Link every advantage to biodegradability.
2. Cloth and jute bags are other good options.

Question 17. What activities do you perform that are good for the biosphere? What activities do you perform that harm the biosphere?
Answer:
Good for the biosphere: reducing the quantity of non-food items bought, reusing things, recycling paper, plastic, glass and metal, carrying cloth bags, planting trees, saving water (not leaving taps running), using public transport or walking, and switching off lights and fans when not in use.
Harmful to the biosphere: using non-recyclable products, driving alone instead of sharing a vehicle, burning plastic, throwing waste in the open, wasting water and electricity, and buying non-essential items in excess.
In simple words: Reduce, reuse and recycle help the biosphere; waste and pollution harm it.

Teacher's Note:
1. Give at least three examples in each column.
2. Write what you really do in daily life.

Question 18. Driving the Swach Bharat Abhiyaan forward, several NGOs are working towards the installation of Blue and Green Dustbins for Municipal Corporations and schools in New Delhi. They are also carrying out a drive to educate children about the segregation of two different kinds of waste. The green is meant for wet waste and the blue one is for dry waste. This way they are separating biodegradable waste from non-biodegradable, thus providing various recycling and composting benefits and keeping the neighbourhood clean and healthy.
(A) There are different methods of waste disposal. The method to be used depends on the nature of the waste. Mention some important methods of waste disposal.
(B) Incineration means reducing to ashes. The burning of a substance at high temperature is called incineration. For what waste, incinerators are used?
(C) Whenever we visit a place of tourist interest, we find the place littered with empty food wrappers and other garbage as heaps lying all over the place. What could be the reasons for generation of heaps of garbage? What do you think will be the impact of these on our environment?
Answer:
(A) Recycling, preparation of compost, incineration, landfills (also sewage treatment and biogas production).
(B) Incinerators are used to destroy hospital (biomedical) waste, chemical waste and some household waste. It greatly reduces the volume of the waste, leaving ash that is disposed of in a landfill.
(C) Reasons: improvements in lifestyle give greater amounts of waste, and changes in packaging make much of it non-biodegradable. Impact: soil contamination, harm to human health, and methane (a greenhouse gas) from heaps of waste can add to global warming.
In simple words: Different wastes need different methods, and heaps of litter pollute the surroundings.

Teacher's Note:
1. Name at least four methods in part (A).
2. Mention soil, health and global warming in part (C).

Question 19. Advitya knows that the Municipal Corporations of most of the cities in India have instructed the people to segregate the waste into two parts: biodegradable and non-biodegradable. But he gets confused whether leather purse, egg shells, even his chocolate wrappers are to be put into which bin and why? Help him classify these wastes according to their nature.
Answer:
The leather purse and egg shells are biodegradable, because microorganisms can decompose them into simpler substances. They go into the bin for biodegradable waste.
The chocolate wrappers are mostly made of plastic or aluminium foil and cannot be decomposed by microorganisms, so they go into the bin for non-biodegradable waste.
Biodegradable waste can be made into manure in a compost pit; non-biodegradable waste can be separated, and the parts can be reused or recycled.
In simple words: Leather and egg shells rot; wrappers do not.

Teacher's Note:
1. Decide by asking whether microbes can break the material down.
2. Say what happens to each kind of waste afterwards.

Question 20. Name the wastes which are generated in your house daily. What measures would you take for their disposal?
Answer:
Wastes generated daily: peels of vegetables and fruits, left-over food, used newspaper, plastic and polythene bags, broken glass and crockery, old clothes and toys.
Measures for disposal: (1) separate biodegradable and non-biodegradable waste and keep them in different bins; (2) make compost from kitchen waste; (3) give old clothes, toys and utensils to needy people for reuse; (4) send paper, plastic and glass for recycling; (5) dispose of polythene bags safely.
In simple words: Sort the waste, compost the wet waste and recycle or reuse the dry waste.

Teacher's Note:
1. List the wastes first and match each with a disposal measure.
2. This is an NCERT Exemplar question.