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
