π CBSE Board |(repeated appearance / board exam trends)
π OUR ENVIRONMENT – CLASS 10
π₯ 30 MOST REPEATED MCQs (TOPIC-WISE)
πΉ TOPIC 1: ECOSYSTEM & ITS COMPONENTS (Q1–Q6)
Q1. Which of the following is a biotic component of an ecosystem?
(a) Air
(b) Water
(c) Plants
(d) Soil
π
Asked in Board Exams: 2017, 2020
Q2. The interaction between biotic and abiotic components takes place in a:
(a) Population
(b) Community
(c) Ecosystem
(d) Biosphere
π
Asked in Board Exams: 2016, 2019
Q3. Which organism is known as a producer?
(a) Deer
(b) Lion
(c) Grass
(d) Human
π
Asked in Board Exams: 2018, 2022
Q4. What is the main source of energy in an ecosystem?
(a) Wind
(b) Water
(c) Sun
(d) Soil
π
Asked in Board Exams: 2015, 2020
Q5. Which of the following is an abiotic factor?
(a) Bacteria
(b) Algae
(c) Fungi
(d) Temperature
π
Asked in Board Exams: 2017, 2021
Q6. Green plants prepare food by the process of:
(a) Respiration
(b) Transpiration
(c) Photosynthesis
(d) Decomposition
π
Asked in Board Exams: 2016, 2019
πΉ TOPIC 2: FOOD CHAIN & FOOD WEB (Q7–Q12)
Q7. The sequence of organisms through which energy flows is called:
(a) Food web
(b) Food chain
(c) Trophic level
(d) Pyramid
π
Asked in Board Exams: 2018, 2023
Q8. Which organism occupies the first trophic level?
(a) Herbivores
(b) Carnivores
(c) Producers
(d) Decomposers
π
Asked in Board Exams: 2017, 2020
Q9. In a food chain, the transfer of energy follows which direction?
(a) Producer → Consumer
(b) Consumer → Producer
(c) Decomposer → Producer
(d) Consumer → Decomposer
π
Asked in Board Exams: 2016, 2022
Q10. Which of the following represents a correct food chain?
(a) Grass → Deer → Lion
(b) Lion → Deer → Grass
(c) Deer → Grass → Lion
(d) Grass → Lion → Deer
π
Asked in Board Exams: 2015, 2019
Q11. Why are food chains usually short?
(a) Loss of energy
(b) More predators
(c) Lack of producers
(d) Climate change
π
Asked in Board Exams: 2018, 2021
Q12. A food web is made up of:
(a) Single food chain
(b) Interconnected food chains
(c) Producers only
(d) Consumers only
π
Asked in Board Exams: 2017, 2020
πΉ TOPIC 3: ENERGY FLOW & TROPHIC LEVEL (Q13–Q18)
Q13. Only about ___% energy is transferred from one trophic level to the next.
(a) 5%
(b) 10%
(c) 20%
(d) 50%
π
Asked in Board Exams: 2016, 2018, 2023
Q14. Which trophic level has maximum energy?
(a) Secondary consumers
(b) Tertiary consumers
(c) Producers
(d) Decomposers
π
Asked in Board Exams: 2019, 2022
Q15. Energy flow in an ecosystem is:
(a) Cyclic
(b) Bidirectional
(c) Unidirectional
(d) Random
π
Asked in Board Exams: 2017, 2021
Q16. Which pyramid always remains upright?
(a) Pyramid of biomass
(b) Pyramid of numbers
(c) Pyramid of energy
(d) Pyramid of organisms
π
Asked in Board Exams: 2018, 2020
Q17. Which organisms decompose dead plants and animals?
(a) Producers
(b) Herbivores
(c) Carnivores
(d) Decomposers
π
Asked in Board Exams: 2016, 2019
Q18. Decomposers return nutrients to the:
(a) Atmosphere
(b) Soil
(c) Water
(d) Sun
π
Asked in Board Exams: 2017, 2022
πΉ TOPIC 4: ENVIRONMENTAL PROBLEMS (Q19–Q24)
Q19. Increase in temperature of the earth is called:
(a) Acid rain
(b) Global warming
(c) Ozone depletion
(d) Green revolution
π
Asked in Board Exams: 2015, 2020
Q20. Which gas is mainly responsible for the greenhouse effect?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Hydrogen
π
Asked in Board Exams: 2016, 2023
Q21. Ozone layer depletion is mainly caused by:
(a) CO₂
(b) CFCs
(c) SO₂
(d) Methane
π
Asked in Board Exams: 2017, 2021
Q22. Excessive use of fertilizers causes:
(a) Air pollution
(b) Water pollution
(c) Noise pollution
(d) Soil erosion
π
Asked in Board Exams: 2018, 2022
Q23. Which of the following is biodegradable?
(a) Plastic
(b) Glass
(c) Paper
(d) Polythene
π
Asked in Board Exams: 2016, 2019
Q24. Burning of fossil fuels mainly causes:
(a) Water pollution
(b) Soil pollution
(c) Air pollution
(d) Noise pollution
π
Asked in Board Exams: 2015, 2020
πΉ TOPIC 5: WASTE MANAGEMENT (Q25–Q30)
Q25. Which method is best for disposal of biodegradable waste?
(a) Recycling
(b) Incineration
(c) Composting
(d) Landfill
π
Asked in Board Exams: 2017, 2023
Q26. Reduce, Reuse and Recycle are called:
(a) 3Rs
(b) 3Cs
(c) 3Ps
(d) 3Ws
π
Asked in Board Exams: 2016, 2018
Q27. Which waste takes the longest time to decompose?
(a) Vegetable peels
(b) Paper
(c) Cotton cloth
(d) Plastic bottle
π
Asked in Board Exams: 2019, 2022
Q28. Vermicomposting uses:
(a) Bacteria
(b) Earthworms
(c) Algae
(d) Fungi
π
Asked in Board Exams: 2017, 2021
Q29. Which practice helps in conserving resources?
(a) Throwing waste
(b) Recycling
(c) Burning waste
(d) Dumping waste
π
Asked in Board Exams: 2016, 2020
Q30. Non-biodegradable waste affects the environment by:
(a) Increasing soil fertility
(b) Causing pollution
(c) Producing oxygen
(d) Supporting life
π
Asked in Board Exams: 2018, 2023
✅ ANSWER KEY (AT THE END)
(c)
(c)
(c)
(c)
(d)
(c)
(b)
(c)
(a)
(a)
(a)
(b)
(b)
(c)
(c)
(c)
(d)
(b)
(b)
(c)
(b)
(b)
(c)
(c)
(c)
(a)
(d)
(b)
(b)
(b)