Our Environment Class 10 MCQs
Our Environment – MCQs with Answers & Explanations
Class: 10 | Subject: Science (Biology)
Section: Our Environment
Based on NCERT & CBSE Board Examination Pattern
Section: Our Environment
Based on NCERT & CBSE Board Examination Pattern
1. All living and non-living components together form:
Answer: B. Ecosystem
An ecosystem includes biotic (living) and abiotic (non-living) components interacting with each other.
An ecosystem includes biotic (living) and abiotic (non-living) components interacting with each other.
2. Green plants are called:
Answer: B. Producers
They prepare food via photosynthesis and form the base of food chains.
They prepare food via photosynthesis and form the base of food chains.
3. Organisms that break down dead matter are:
Answer: C. Decomposers
Bacteria and fungi recycle nutrients back to soil.
Bacteria and fungi recycle nutrients back to soil.
4. First trophic level consists of:
Answer: C. Producers
Energy enters ecosystem through producers.
Energy enters ecosystem through producers.
5. Energy flow in ecosystem is:
Answer: B. Unidirectional
Energy flows from sun → producers → consumers and is lost as heat.
Energy flows from sun → producers → consumers and is lost as heat.
6. 10% law relates to:
Answer: B. Energy transfer
Only ~10% energy passes to next trophic level.
Only ~10% energy passes to next trophic level.
7. Food chain shows:
Answer: A.
It represents feeding relationships and energy flow.
It represents feeding relationships and energy flow.
8. Interconnected food chains form:
Answer: A.
Food webs increase ecosystem stability.
Food webs increase ecosystem stability.
9. Pyramid of energy is always:
Answer: B.
Energy decreases at each trophic level.
Energy decreases at each trophic level.
10. Ozone layer protects from:
Answer: B.
Ozone absorbs harmful ultraviolet radiation.
Ozone absorbs harmful ultraviolet radiation.
11. Ozone depletion is caused by:
Answer: B.
Chlorofluorocarbons break ozone molecules.
Chlorofluorocarbons break ozone molecules.
12. Non-biodegradable waste includes:
Answer: B.
Plastic persists and pollutes ecosystems.
Plastic persists and pollutes ecosystems.
13. Biological magnification refers to:
Answer: B.
Toxic substances accumulate at higher trophic levels.
Toxic substances accumulate at higher trophic levels.
14. DDT accumulation affects:
Answer: B.
Magnification increases toxin concentration upward.
Magnification increases toxin concentration upward.
15. Biodegradable wastes are decomposed by:
Answer: B.
Microorganisms recycle organic matter.
Microorganisms recycle organic matter.
16. Sun is ultimate source of:
Answer: B.
All food chains start with solar energy.
All food chains start with solar energy.
17. Role of decomposers in ecosystem:
Answer: B.
They maintain nutrient cycles.
They maintain nutrient cycles.
18. Example of primary consumer:
Answer: B.
Herbivores feed on producers.
Herbivores feed on producers.
19. Ecosystem balance depends on:
Answer: A.
Interlinked feeding relationships maintain balance.
Interlinked feeding relationships maintain balance.
20. Best method to manage waste:
Answer: B.
Recycling conserves resources and reduces pollution.
Recycling conserves resources and reduces pollution.