Extra 30 short answer questions for the chapter:13 "Our Environment" from Class 10 CBSE Science:

 

What is an ecosystem? Give two examples.
Ans: An ecosystem is a biological community of interacting organisms and their physical environment. Examples: Forest, Pond.

 

Differentiate between biotic and abiotic components with examples.
Ans:

Biotic components: Living organisms (e.g., plants, animals, bacteria).

Abiotic components: Non-living things (e.g., water, sunlight, temperature).

 

What are producers? Give an example.
Ans: Producers are organisms that make their own food through photosynthesis. Example: Green plants.

 

Define decomposers and state their role in the environment.
Ans: Decomposers break down dead plants and animals, recycling nutrients back into the ecosystem. Example: Bacteria, fungi.

 

What is a food chain? Give an example.
Ans: A food chain shows the transfer of energy from one organism to another. Example: Grass → Grasshopper → Frog → Snake → Hawk.

 

What is a food web? How is it different from a food chain?
Ans: A food web is a network of interconnected food chains in an ecosystem. Unlike a food chain, it shows multiple feeding relationships.

 

What is meant by trophic level?
Ans: A trophic level is the position an organism occupies in a food chain, such as producers, primary consumers, secondary consumers, and decomposers.

 

What is the 10% Law? Who proposed it?
Ans: The 10% Law states that only 10% of energy is transferred from one trophic level to the next. Proposed by Raymond Lindeman.

 

Why do food chains have only 3-4 trophic levels?
Ans: Due to energy loss at each level, a longer food chain would not have enough energy to sustain higher trophic levels.

 

Why are decomposers necessary in the ecosystem?
Ans: They break down organic matter, recycle nutrients, and maintain soil fertility.

 

What are biodegradable and non-biodegradable substances? Give examples.
Ans:

Biodegradable: Can be broken down naturally (e.g., paper, food waste).

Non-biodegradable: Cannot be broken down easily (e.g., plastic, glass).

 

Why are plastic bags harmful to the environment?
Ans: They are non-biodegradable, cause soil and water pollution, and harm animals when ingested.

 

What are the causes of ozone layer depletion?
Ans: Ozone depletion is mainly caused by CFCs (Chlorofluorocarbons) found in aerosols, refrigerators, and air conditioners.

 

What are the effects of ozone layer depletion?
Ans:

Increased UV radiation, causing skin cancer & cataracts.

Reduced crop yield and weakened immune system.

 

What are greenhouse gases? Name two examples.
Ans: Greenhouse gases trap heat in the atmosphere. Examples: Carbon dioxide (CO₂), Methane (CH₄).

 

What is biomagnification? Explain with an example.
Ans: Biomagnification is the increase in toxin concentration at higher trophic levels. Example: Pesticides like DDT accumulating in birds.

 

What are the harmful effects of excessive use of pesticides and fertilizers?
Ans:

Soil and water pollution.

Kills beneficial microorganisms.

Leads to biomagnification in the food chain.

 

How does deforestation affect the environment?
Ans:

Increases carbon dioxide levels, leading to global warming.

Causes soil erosion and loss of biodiversity.

 

Why should we avoid using plastic bags?
Ans: They are non-biodegradable, clog drains, pollute soil, and harm marine life when disposed of in water.

 

What is e-waste? How does it affect the environment?
Ans: E-waste consists of discarded electronic devices like mobiles and computers. It releases toxic metals, polluting air, water, and soil.

 

What are the three R’s of waste management? Explain.
Ans:

Reduce: Minimize waste production.

Reuse: Use materials multiple times.

Recycle: Convert waste into reusable materials.

 

What is the importance of the ozone layer?
Ans: It protects life on Earth by absorbing harmful UV radiation from the Sun.

 

How does air pollution affect human health?
Ans: Causes respiratory diseases, lung cancer, asthma, and eye irritation.

 

What are the major causes of global warming?
Ans:

Excessive fossil fuel burning.

Deforestation, reducing CO₂ absorption.

Increased greenhouse gases.

 

What are the advantages of using biodegradable materials?
Ans: They reduce pollution, decompose naturally, and do not harm wildlife.

 

How can we reduce plastic pollution?
Ans:

Use cloth or paper bags.

Ban single-use plastics.

Promote recycling and reusing plastic items.

 

What is the effect of deforestation on carbon dioxide levels?
Ans: Deforestation reduces oxygen production and increases CO₂ levels, leading to global warming.

 

How can we protect the ozone layer?
Ans:

Reduce CFC usage in refrigerators and air conditioners.

Use ozone-friendly products.

Promote tree plantation to absorb CO₂.

 

How does excessive use of chemical fertilizers affect soil fertility?
Ans:

Depletes natural soil nutrients.

Kills microorganisms essential for soil health.

Leads to water pollution through runoff.

 

How does sustainable development help the environment?
Ans:

Uses resources wisely for future generations.

Reduces pollution and deforestation.

Promotes renewable energy sources.