CBSE Class 10 Science Biology
Our Environment Important Questions and Answers for Class 10 CBSE
NCERT + Board Exam + Exemplar + Olympiad level question bank covering ecosystem, food chains, food webs, trophic levels, energy flow, 10% law, biodegradable and non-biodegradable waste, biomagnification, ozone layer depletion and environmental protection.
Short Introduction
The chapter Our Environment explains how living organisms interact with each other and with the physical environment. It includes important concepts such as ecosystem, producers, consumers, decomposers, food chains, food webs, trophic levels, flow of energy, 10 percent law, ecological balance, biodegradable and non-biodegradable substances, biomagnification, ozone layer depletion and waste management. This chapter is highly scoring in CBSE board exams because it contains reasoning-based, case-study and competency-based questions.
Chapter Overview
Ecosystem
An ecosystem includes living organisms and non-living components interacting as a functional unit.
Food Chain
A food chain shows the transfer of food and energy from one organism to another.
Food Web
A food web is a network of interconnected food chains found in nature.
Energy Flow
Energy flows from the sun to producers and then to consumers in one direction.
Biomagnification
Harmful chemicals increase in concentration at higher trophic levels.
Ozone Layer
The ozone layer protects living organisms from harmful ultraviolet radiation.
Important Keywords
Important Very Short Answer Questions
Q1. What is environment?
Answer: Environment includes all living and non-living things around an organism that affect its life.
Q2. What is an ecosystem?
Answer: An ecosystem is a self-sustaining unit in which living organisms interact with each other and with non-living components.
Q3. Name two biotic components of an ecosystem.
Answer: Plants and animals are two biotic components of an ecosystem.
Q4. Name two abiotic components of an ecosystem.
Answer: Air and water are two abiotic components of an ecosystem.
Q5. Why are green plants called producers?
Answer: Green plants are called producers because they prepare food by photosynthesis using sunlight, carbon dioxide and water.
Q6. What are consumers?
Answer: Consumers are organisms that depend directly or indirectly on producers for food.
Q7. What are decomposers?
Answer: Decomposers are organisms that break down dead plants, animals and organic wastes into simpler substances.
Q8. Give one example of a decomposer.
Answer: Bacteria or fungi.
Q9. What is a food chain?
Answer: A food chain is a sequence of organisms through which food and energy pass from one organism to another.
Q10. What is a trophic level?
Answer: Each step or level in a food chain is called a trophic level.
Q11. What is the 10 percent law?
Answer: According to the 10 percent law, only about 10 percent of energy is transferred from one trophic level to the next.
Q12. What is biomagnification?
Answer: Biomagnification is the increase in concentration of harmful chemicals at higher trophic levels of a food chain.
Q13. What are biodegradable substances?
Answer: Substances that can be broken down by microorganisms into simpler harmless substances are called biodegradable substances.
Q14. What are non-biodegradable substances?
Answer: Substances that cannot be broken down easily by microorganisms are called non-biodegradable substances.
Q15. What is the main function of the ozone layer?
Answer: The ozone layer protects living organisms from harmful ultraviolet radiation from the sun.
Q16. Which chemicals are mainly responsible for ozone layer depletion?
Answer: Chlorofluorocarbons, commonly called CFCs, are mainly responsible for ozone layer depletion.
Short Answer Questions
Q1. A pond has fish, algae, insects, water, sunlight and dissolved oxygen. Why is it called an ecosystem?
Answer: A pond is called an ecosystem because it has biotic components such as fish, algae and insects, and abiotic components such as water, sunlight and dissolved oxygen. These components interact with each other and function as a unit.
Q2. Why are producers placed at the first trophic level?
Answer: Producers are placed at the first trophic level because they trap solar energy and convert it into chemical energy in food through photosynthesis. All other organisms depend directly or indirectly on producers.
Q3. Why are decomposers called natural cleaners?
Answer: Decomposers break down dead organisms and organic waste into simpler substances. They clean the environment and return nutrients to the soil, making them available for plants again.
Q4. What would happen if decomposers were absent from the ecosystem?
Answer:
- Dead plants, animals and organic wastes would accumulate.
- Nutrients would not be recycled back into the soil.
- Soil fertility would decrease.
- The balance of the ecosystem would be disturbed.
Q5. Why is energy flow in an ecosystem unidirectional?
Answer: Energy flows from the sun to producers and then to consumers. At every trophic level, a large amount of energy is lost as heat. This lost energy does not return to the previous trophic level, so energy flow is unidirectional.
Q6. Why are food chains usually short?
Answer: Food chains are usually short because only about 10 percent of energy is transferred to the next trophic level. After three or four levels, very little energy remains to support more organisms.
Q7. Differentiate between food chain and food web.
| Food Chain | Food Web |
|---|---|
| It is a single pathway of energy transfer. | It is a network of interconnected food chains. |
| It is simple and linear. | It is complex and branched. |
| Example: Grass → Deer → Lion | Example: Grass may be eaten by deer, goat, rabbit and insects. |
| Less stable. | More stable because organisms have alternate food sources. |
Q8. Why is a food web more stable than a food chain?
Answer: A food web provides alternate food sources to organisms. If one food source decreases, organisms can depend on another. This makes a food web more stable than a single food chain.
Q9. Why do harmful chemicals show maximum concentration in top carnivores?
Answer: Non-biodegradable chemicals such as pesticides enter the food chain and are not easily broken down. Their concentration increases at each trophic level. Therefore, top carnivores receive the highest concentration of these chemicals.
Q10. Why is plastic harmful for the environment?
Answer: Plastic is non-biodegradable. It persists in the environment for a long time, pollutes soil and water, harms animals and may enter food chains as microplastics.
Q11. Why is ozone layer important for life on Earth?
Answer: The ozone layer absorbs harmful ultraviolet radiation from the sun. Without the ozone layer, UV radiation can cause skin cancer, eye damage, reduced crop yield and harm to aquatic life.
Q12. How can waste be managed at home?
Answer: Waste can be managed by separating biodegradable and non-biodegradable waste, composting kitchen waste, recycling paper, glass and metal, reusing materials and avoiding single-use plastic.
Long Answer Questions
Q1. Explain the components of an ecosystem with examples.
Answer: An ecosystem has two main components: biotic components and abiotic components.
- Biotic components: These are living components such as plants, animals, bacteria and fungi.
- Abiotic components: These are non-living components such as air, water, sunlight, soil, temperature and minerals.
Biotic components are further divided into:
- Producers: Green plants and algae that prepare food by photosynthesis.
- Consumers: Organisms that depend on producers or other organisms for food.
- Decomposers: Bacteria and fungi that break down dead organisms and recycle nutrients.
Q2. Explain food chain with an example and identify trophic levels.
Answer: A food chain shows the transfer of food and energy from one organism to another.
Grass → Grasshopper → Frog → Snake → Eagle
| Organism | Trophic Level | Role |
|---|---|---|
| Grass | First trophic level | Producer |
| Grasshopper | Second trophic level | Primary consumer |
| Frog | Third trophic level | Secondary consumer |
| Snake | Fourth trophic level | Tertiary consumer |
| Eagle | Fifth trophic level | Top carnivore |
Q3. Explain the 10 percent law of energy transfer.
Answer: According to the 10 percent law, only about 10 percent of energy available at one trophic level is transferred to the next trophic level. The remaining energy is used in life processes or lost as heat.
Example:
Plants: 10,000 J → Deer: 1,000 J → Lion: 100 J
- Plants receive energy from the sun.
- Only about 10 percent of plant energy is transferred to herbivores.
- Only about 10 percent of herbivore energy is transferred to carnivores.
- This explains why food chains usually have limited trophic levels.
Q4. Explain why decomposers are essential for nutrient recycling.
Answer: Decomposers such as bacteria and fungi break down dead organisms and organic waste into simpler substances. These substances mix with soil and are absorbed by plants as nutrients. Without decomposers, nutrients would remain locked in dead matter and would not return to the ecosystem. Thus, decomposers maintain soil fertility and ecological balance.
Q5. Compare biodegradable and non-biodegradable substances.
| Biodegradable Substances | Non-Biodegradable Substances |
|---|---|
| Can be broken down by microorganisms. | Cannot be broken down easily by microorganisms. |
| Do not remain in the environment for a very long time. | Remain in the environment for many years. |
| Usually cause less long-term pollution. | Cause long-term soil, water and air pollution. |
| Examples: Vegetable peels, paper, cotton cloth, leaves. | Examples: Plastic, glass, DDT, metal cans, synthetic fibres. |
Q6. Explain biological magnification with an example.
Answer: Biological magnification, also called biomagnification, is the increase in concentration of non-biodegradable harmful chemicals at successive trophic levels in a food chain.
Example:
Water → Plankton → Small fish → Large fish → Birds / Humans
- Pesticides or chemicals enter water bodies through agricultural runoff.
- Plankton absorb these chemicals.
- Small fish eat many plankton and accumulate more chemicals.
- Large fish eat many small fish and accumulate even more chemicals.
- Top consumers receive the highest concentration of chemicals.
Q7. Explain ozone layer depletion and its harmful effects.
Answer: The ozone layer is present in the upper atmosphere and protects Earth from harmful ultraviolet radiation. Ozone depletion means thinning of this protective layer.
Causes:
- CFCs released from refrigerators, air conditioners and aerosol sprays.
- CFCs reach the upper atmosphere and release chlorine atoms.
- Chlorine atoms break down ozone molecules, reducing the ozone layer.
Harmful effects:
- Increased risk of skin cancer.
- Eye damage such as cataract.
- Damage to crops and plants.
- Harm to aquatic organisms and plankton.
- Weakening of immune system in humans and animals.
Q8. Explain how human activities disturb ecological balance.
Answer: Human activities can disturb ecological balance in many ways:
- Excessive use of pesticides causes biomagnification.
- Deforestation destroys habitats and reduces biodiversity.
- Plastic waste pollutes soil and water.
- Industrial waste contaminates rivers and lakes.
- Burning fossil fuels increases air pollution.
- Use of CFCs causes ozone layer depletion.
To protect the environment, humans should reduce waste, recycle materials, use biodegradable products, conserve forests and reduce pollution.
Important Tables for Quick Learning
Types of Consumers
| Type of Consumer | Food Habit | Example |
|---|---|---|
| Herbivore | Eats plants | Deer, rabbit, cow |
| Carnivore | Eats other animals | Lion, snake, eagle |
| Omnivore | Eats both plants and animals | Human, crow, bear |
| Decomposer | Breaks down dead organic matter | Bacteria, fungi |
Food Chain and Energy Transfer
| Trophic Level | Organism Type | Example | Energy Available Example |
|---|---|---|---|
| First | Producer | Grass | 10,000 J |
| Second | Primary consumer | Grasshopper | 1,000 J |
| Third | Secondary consumer | Frog | 100 J |
| Fourth | Tertiary consumer | Snake | 10 J |
Waste Management Methods
| Method | Used For | Benefit |
|---|---|---|
| Composting | Kitchen waste, leaves, vegetable peels | Produces manure and reduces waste |
| Recycling | Paper, glass, metal, some plastics | Saves resources and reduces pollution |
| Reuse | Bottles, bags, containers | Reduces demand for new products |
| Segregation | Wet and dry waste | Makes waste treatment easier |
NCERT Exemplar Level Questions
Q1. A food chain has plants, insects, frogs, snakes and eagles. If pesticides enter this food chain, which organism will have the maximum concentration?
Answer: Eagles will have the maximum concentration because they are at the highest trophic level. Non-biodegradable pesticides increase in concentration through biomagnification.
Q2. A farmer uses excessive pesticides on crops. Explain how this can affect humans.
Answer: Pesticides may enter the food chain through crops. Since many pesticides are non-biodegradable, they accumulate in organisms and increase at higher trophic levels. Humans may consume contaminated food and suffer health problems.
Q3. Why is a food web a better representation of feeding relationships in nature than a food chain?
Answer: In nature, most organisms have more than one food source and may be eaten by more than one predator. A food web shows these interconnected feeding relationships, so it is more realistic than a single food chain.
Q4. Why does energy decrease as we move from producers to top consumers?
Answer: At each trophic level, organisms use most of the energy for life processes such as respiration, movement, growth and reproduction. Much energy is lost as heat, so only about 10 percent is passed to the next level.
Q5. Why are decomposers not always shown in a food chain diagram though they are very important?
Answer: Food chain diagrams usually show feeding relationships among producers and consumers. Decomposers act on dead remains of organisms at all trophic levels, so they are not always shown in the main linear chain but are essential for nutrient recycling.
Q6. A student says that all biodegradable substances are harmless. Is this statement correct?
Answer: No. Biodegradable substances can be decomposed by microorganisms, but if they are present in very large quantities, they may cause pollution, foul smell, growth of pathogens and oxygen depletion in water bodies.
Q7. Why should non-biodegradable waste be recycled?
Answer: Non-biodegradable waste remains in the environment for a long time. Recycling reduces pollution, saves raw materials, reduces landfill pressure and prevents harmful substances from entering food chains.
Q8. Why are top carnivores fewer in number than herbivores?
Answer: Top carnivores receive very little energy because energy decreases at each trophic level. Therefore, an ecosystem can support fewer top carnivores compared to herbivores.
Numerical and Reasoning Questions on 10 Percent Law
Q1. If plants have 20,000 J of energy, how much energy will be available to herbivores and secondary consumers?
Solution:
According to the 10 percent law:
Energy to herbivores = 10% of 20,000 J = 2,000 J
Energy to secondary consumers = 10% of 2,000 J = 200 J
Answer: Herbivores get 2,000 J and secondary consumers get 200 J.
Q2. In a food chain, a snake receives 50 J of energy. How much energy was available at the previous trophic level?
Solution:
If snake receives 10 percent energy from the previous trophic level:
Previous trophic level energy = 50 × 10 = 500 J
Answer: The previous trophic level had 500 J of energy.
Q3. A food chain is: Grass → Deer → Tiger. If tiger receives 100 J of energy, how much energy was present in grass?
Solution:
Tiger receives 10 percent energy from deer, so deer had:
100 × 10 = 1,000 J
Deer receives 10 percent energy from grass, so grass had:
1,000 × 10 = 10,000 J
Answer: Grass had 10,000 J of energy.
Q4. Why is only 10 percent energy transferred to the next trophic level?
Answer: Most of the energy is used by organisms for respiration, movement, growth, reproduction and other life processes. Some energy is lost as heat. Therefore, only about 10 percent energy is stored as biomass and transferred to the next trophic level.
Case-Study Based Questions
Case Study 1: Pesticides in a Lake
A lake receives water from nearby farms where pesticides are used. The lake has algae, small fish, large fish and fish-eating birds. After some time, scientists find the highest pesticide concentration in fish-eating birds.
Q1. Which phenomenon is shown in this case?
Answer: Biological magnification or biomagnification.
Q2. Why do birds have the highest pesticide concentration?
Answer: Birds are at the highest trophic level. Non-biodegradable pesticides accumulate and increase in concentration at each trophic level.
Q3. Write the possible food chain.
Answer:
Algae → Small fish → Large fish → Fish-eating birds
Case Study 2: Plastic Waste
A town uses large amounts of single-use plastic bags. Many bags are thrown in open areas and drains. Animals sometimes eat them, and drains get blocked during rainfall.
Q1. Is plastic biodegradable or non-biodegradable?
Answer: Plastic is non-biodegradable.
Q2. Why is plastic waste dangerous?
Answer: It persists for a long time, blocks drains, pollutes soil and water, and may harm animals if eaten.
Q3. Suggest two ways to reduce this problem.
Answer: Use cloth or jute bags and recycle plastic waste properly.
Case Study 3: Forest Food Web
In a forest, grass is eaten by deer, rabbits and insects. Frogs eat insects. Snakes eat frogs and rabbits. Eagles eat snakes. Lions eat deer.
Q1. Why is this an example of a food web?
Answer: It shows many interconnected food chains instead of a single feeding pathway.
Q2. What may happen if insects decrease suddenly?
Answer: Frogs may face shortage of food. This can also affect snakes that eat frogs. However, the food web may remain partly stable because snakes may also eat rabbits.
Q3. Identify one producer and one top consumer.
Answer: Grass is a producer. Eagle or lion is a top consumer.
Case Study 4: Ozone Layer
Scientists observed thinning of the ozone layer due to excessive release of certain chemicals used in refrigerators and aerosol sprays.
Q1. Name the chemicals responsible for ozone depletion.
Answer: Chlorofluorocarbons or CFCs.
Q2. Why is ozone layer important?
Answer: It absorbs harmful ultraviolet radiation from the sun and protects living organisms.
Q3. Write one harmful effect of ozone layer depletion.
Answer: It can increase skin cancer and eye damage in humans.
Critical Thinking Questions
Q1. Why is the removal of one species more harmful in a simple food chain than in a food web?
Answer: In a simple food chain, each organism depends on a single food source. If one species is removed, energy transfer is disturbed. In a food web, organisms have alternate food sources, so the effect may be less severe.
Q2. Why can humans be badly affected by pesticides even if they are not sprayed directly on humans?
Answer: Pesticides can enter crops, soil and water. They move through food chains and get concentrated at higher trophic levels. Humans may consume contaminated food and accumulate these chemicals in their bodies.
Q3. Why do vegetarian food habits usually require less energy from the ecosystem than non-vegetarian food habits?
Answer: Eating plants means consuming food at a lower trophic level where more energy is available. Eating animals involves higher trophic levels where much energy has already been lost, so more plant biomass is needed to support non-vegetarian food chains.
Q4. Why is burning plastic not a good solution for waste disposal?
Answer: Burning plastic releases toxic gases and harmful pollutants. It can cause air pollution and health problems. Recycling, reducing and proper disposal are better options.
Q5. Why should biodegradable and non-biodegradable waste be separated?
Answer: Separation helps in proper treatment. Biodegradable waste can be composted, while non-biodegradable waste can be recycled or safely disposed of. Mixing them makes waste management difficult.
Q6. Why are top carnivores important even though they are fewer in number?
Answer: Top carnivores regulate the population of herbivores and smaller carnivores. This helps maintain ecological balance and prevents overgrazing or overpopulation of certain species.
Q7. Why does biomagnification mainly occur with non-biodegradable chemicals?
Answer: Non-biodegradable chemicals are not easily broken down or excreted. They remain stored in the bodies of organisms and increase in concentration at successive trophic levels.
Q8. Why does the ozone layer affect aquatic life indirectly?
Answer: Ozone layer depletion allows more UV radiation to reach Earth. UV radiation can harm plankton and other small aquatic organisms, which form the base of aquatic food chains. This affects the whole aquatic ecosystem.
Q9. Why is composting better than dumping kitchen waste in open areas?
Answer: Composting converts kitchen waste into useful manure in a controlled way. Open dumping causes foul smell, attracts disease-causing organisms and pollutes surroundings.
Q10. Why is energy pyramid usually upright?
Answer: Energy decreases at each successive trophic level due to loss of energy as heat and use in life processes. Therefore, producers have maximum energy and top consumers have minimum energy, making the energy pyramid upright.
Previous Year Board Exam Pattern Questions
Q1. What are trophic levels? Give an example.
Answer: Each step in a food chain is called a trophic level. Example: In the food chain Grass → Deer → Lion, grass is the first trophic level, deer is the second trophic level and lion is the third trophic level.
Q2. Why is the flow of energy in an ecosystem unidirectional?
Answer: Energy flows from sun to producers and then to consumers. At each trophic level, energy is lost as heat and cannot be returned to the previous level. Hence, energy flow is unidirectional.
Q3. What are decomposers? State their role in the ecosystem.
Answer: Decomposers are microorganisms such as bacteria and fungi that break down dead organisms and organic waste. They recycle nutrients, clean the environment and maintain soil fertility.
Q4. Why are some substances biodegradable and some non-biodegradable?
Answer: Some substances can be broken down by enzymes of microorganisms, so they are biodegradable. Some substances have complex synthetic structures that microorganisms cannot break down easily, so they are non-biodegradable.
Q5. Explain biological magnification.
Answer: Biological magnification is the increase in concentration of harmful non-biodegradable chemicals at successive trophic levels in a food chain. It is maximum in top consumers.
Q6. Why is ozone layer depletion a serious environmental problem?
Answer: Ozone layer depletion allows more harmful UV radiation to reach Earth. This can cause skin cancer, eye damage, harm to crops and damage to aquatic life.
Q7. Give two ways to reduce non-biodegradable waste.
Answer: Two ways are recycling non-biodegradable materials and reducing the use of single-use plastic products.
Q8. Why is food web important for ecosystem stability?
Answer: A food web provides multiple feeding options to organisms. If one organism becomes less available, another food source may support the consumer. This increases ecosystem stability.
Olympiad Level Questions
Q1. In a food chain, producers store 50,000 J of energy. How much energy will reach the tertiary consumer?
Solution:
Producer energy = 50,000 J
Primary consumer gets 10% = 5,000 J
Secondary consumer gets 10% = 500 J
Tertiary consumer gets 10% = 50 J
Answer: The tertiary consumer receives 50 J of energy.
Q2. If a harmful chemical enters a food chain at producer level, why does its concentration not follow the 10 percent energy rule?
Answer: The 10 percent law applies to energy transfer, not to non-biodegradable chemicals. Such chemicals are not easily broken down or removed, so they accumulate and increase at higher trophic levels.
Q3. Which ecosystem is more stable: one with a single food chain or one with many interconnected food chains? Explain.
Answer: An ecosystem with many interconnected food chains is more stable because it forms a food web. Organisms have alternate food sources, so the loss of one species does not completely stop energy transfer.
Q4. Why is the number of organisms generally maximum at producer level and minimum at top carnivore level?
Answer: Producers have the maximum available energy. Energy decreases at each trophic level, so fewer organisms can be supported at higher levels. Therefore, top carnivores are fewer in number.
Q5. A lake receives sewage rich in organic waste. What may happen to oxygen level in the lake?
Answer: Microorganisms decompose the organic waste and consume dissolved oxygen. This reduces oxygen level in water and may harm fish and other aquatic organisms.
Q6. Why are synthetic pesticides more dangerous than many natural wastes?
Answer: Many synthetic pesticides are non-biodegradable and persist in the environment. They can enter food chains, accumulate in organisms and cause biomagnification.
Assertion-Reason Questions
Choose the correct option:
A. Both Assertion and Reason are true and Reason is the correct explanation.
B. Both Assertion and Reason are true but Reason is not the correct explanation.
C. Assertion is true but Reason is false.
D. Assertion is false but Reason is true.
Q1. Assertion: Producers form the first trophic level. Reason: Producers trap solar energy and prepare food by photosynthesis.
Answer: A. Both Assertion and Reason are true and Reason is the correct explanation.
Q2. Assertion: Food chains are usually short. Reason: Only about 10 percent energy is transferred to the next trophic level.
Answer: A. Both Assertion and Reason are true and Reason is the correct explanation.
Q3. Assertion: Decomposers recycle nutrients in an ecosystem. Reason: Decomposers break down dead organisms into simpler substances.
Answer: A. Both Assertion and Reason are true and Reason is the correct explanation.
Q4. Assertion: Non-biodegradable chemicals show biomagnification. Reason: These chemicals are easily broken down by microorganisms.
Answer: C. Assertion is true but Reason is false. Non-biodegradable chemicals are not easily broken down.
Q5. Assertion: Ozone layer protects life on Earth. Reason: Ozone layer absorbs harmful ultraviolet radiation.
Answer: A. Both Assertion and Reason are true and Reason is the correct explanation.
Q6. Assertion: Food web is more stable than food chain. Reason: Food web provides alternate feeding pathways.
Answer: A. Both Assertion and Reason are true and Reason is the correct explanation.
Quick Revision Box
Functional Unit
Ecosystem
First Trophic Level
Producers
Natural Cleaners
Decomposers
Energy Transfer
10 percent law
Energy Flow
Unidirectional
Stable Feeding Network
Food web
Highest Chemical Accumulation
Top consumers
Ozone Depleting Chemicals
CFCs
Ozone Protects From
UV radiation
Exam Tips
Interactive Practice Zone
Food Chain Energy Calculator
Enter energy available at producer level and calculate energy at higher trophic levels using the 10 percent law.
Waste Type Checker
Select a material and check whether it is biodegradable or non-biodegradable.
Mini Quiz
Which organisms receive the highest concentration of pesticides in a food chain?
FAQ Section
What is an ecosystem?
An ecosystem is a functional unit where living organisms interact with each other and with non-living components.
What are producers?
Producers are organisms such as green plants that prepare food by photosynthesis.
Why are decomposers important?
Decomposers break down dead organisms and organic waste, recycle nutrients and keep the environment clean.
What is the 10 percent law?
The 10 percent law states that only about 10 percent of energy is transferred from one trophic level to the next.
What is biomagnification?
Biomagnification is the increase in concentration of harmful non-biodegradable chemicals at higher trophic levels.
Why are food chains short?
Food chains are short because energy decreases sharply at each trophic level due to the 10 percent law.
What causes ozone layer depletion?
Ozone layer depletion is mainly caused by CFCs released from refrigerators, air conditioners and aerosol sprays.
How can we reduce environmental pollution?
We can reduce pollution by waste segregation, recycling, composting, reducing plastic use, planting trees and using eco-friendly products.
Final Conclusion
Our Environment is an important Class 10 Science chapter that connects biology with real-life environmental issues. Students should understand ecosystem components, food chains, food webs, trophic levels, 10 percent law, decomposers, biodegradable and non-biodegradable waste, biomagnification and ozone layer depletion. Practising reasoning-based, case-study and numerical questions will help students score high marks in CBSE board exams and also develop environmental awareness.
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