Class 10 Science Our Environment Fill in the blanks , Multiple Choice Question [mcq] and True false .
Fill in the Blanks
1. An ecosystem consists of ________ (biotic) and ________ (abiotic) components.
2. The process by which green plants make food using sunlight is called ________ (photosynthesis).
3. Organisms that break down dead matter into simpler substances are called ________ (decomposers).
4. The flow of energy in an ecosystem is ________ (unidirectional).
5. The phenomenon where harmful chemicals accumulate in higher trophic levels is called ________ (biological magnification).
6. Ozone layer protects Earth from harmful ________ (ultraviolet/UV) radiation.
7. CFCs (Chlorofluorocarbons) are responsible for the depletion of the ________ (ozone) layer.
8. Plastics are examples of ________ (non-biodegradable) waste.
9. A series of organisms feeding on one another forms a ________ (food chain).
10. Only ________ (10%) of energy is transferred to the next trophic level.
11. Human-made ecosystems include ________ (aquariums) and ________ (crop fields).
12. The first trophic level in a food chain consists of ________ (producers).
13. Waste materials that can be broken down naturally are called ________ (biodegradable).
14. The United Nations Environment Programme (UNEP) regulates the use of ________ (CFCs).
15. Disposable paper cups are better than plastic cups because they are ________ (biodegradable).
Multiple Choice Questions (MCQs)
1. Which of the following is a natural ecosystem?
a) Garden
b) Aquarium
c) Forest
d) Crop field
Answer: c) Forest
2. What percentage of energy is transferred to the next trophic level?
a) 1%
b) 10%
c) 50%
d) 90%
Answer: b) 10%
3. Which gas protects Earth from UV radiation?
a) Oxygen (O₂)
b) Carbon dioxide (CO₂)
c) Ozone (O₃)
d) Nitrogen (N₂)
Answer: c) Ozone (O₃)
4. What is the role of decomposers in an ecosystem?
a) Produce oxygen
b) Break down dead matter
c) Trap sunlight
d) Pollinate flowers
Answer: b) Break down dead matter
5. Which of the following is non-biodegradable?
a) Vegetable peels
b) Paper
c) Plastic
d) Wood
Answer: c) Plastic
6. The primary consumers in a food chain are:
a) Carnivores
b) Herbivores
c) Decomposers
d) Producers
Answer: b) Herbivores
7. What causes biological magnification?
a) Oxygen accumulation
b) Pesticide accumulation
c) Excess sunlight
d) Water pollution
Answer: b) Pesticide accumulation
8. Which of the following is a human-made ecosystem?
a) Pond
b) Lake
c) Aquarium
d) Ocean
Answer: c) Aquarium
9. The maximum concentration of chemicals in a food chain is found in:
a) Producers
b) Primary consumers
c) Top carnivores
d) Decomposers
Answer: c) Top carnivores
10. Which agreement regulates CFC production?
a) Kyoto Protocol
b) UNEP Agreement
c) Paris Agreement
d) Montreal Protocol
Answer: b) UNEP Agreement
11. What is the main source of energy in an ecosystem?
a) Water
b) Soil
c) Sun
d) Air
Answer: c) Sun
12. Which trophic level has the maximum number of organisms?
a) Producers
b) Primary consumers
c) Secondary consumers
d) Tertiary consumers
Answer: a) Producers
13. Which of the following is biodegradable?
a) Glass bottle
b) Aluminium foil
c) Fruit peel
d) Polythene bag
Answer: c) Fruit peel
14. What happens if decomposers are removed from an ecosystem?
a) Energy flow increases
b) Dead matter accumulates
c) More oxygen is produced
d) Food chains become shorter
Answer: b) Dead matter accumulates
15. Which of these is an environment-friendly practice?
a) Using plastic bags
b) Burning waste
c) Carrying cloth bags
d) Leaving lights on
Answer: c) Carrying cloth bags
True or False
1. Producers are the first trophic level in a food chain. Answer: True
2. Energy flow in an ecosystem is cyclic. Answer: False (It is unidirectional)
3. CFCs help in protecting the ozone layer. Answer: False (They deplete it)
4. All waste generated by humans is biodegradable. Answer: False (e.g., plastics are non-biodegradable)
5. Decomposers convert dead matter into nutrients. Answer: True
6. A food web consists of multiple interconnected food chains. Answer: True
7. Biological magnification benefits top consumers. Answer: False (It harms them due to toxin accumulation)
8. Ozone is harmful at ground level but beneficial in the stratosphere. Answer: True
9. Paper cups are non-biodegradable. Answer: False (They are biodegradable)
10. Only 1% of sunlight energy is captured by plants. Answer: True
11. Aquarium is a natural ecosystem. Answer: False (It is human-made)
12. Herbivores are secondary consumers. Answer: False (They are primary consumers)
13. Plastics decompose quickly in soil. Answer: False (They are non-biodegradable)
14. The ozone hole is caused by excess oxygen. Answer: False (It’s caused by CFCs)
15. Using reusable bags reduces waste. Answer: True
