Our Environment: Class 10 Previous Year Questions

Our Environment questions asked in CBSE board exams

Repeated questions first. Open the free app to see each question as it appeared in the paper, with its marking scheme.

1. Which of the following limits the number of trophic levels in a food chain ? 1 (A) Availability of water (B) Deficient food supply (C) Decrease in energy at higher levels (D) Pollution in air.
   Board 20261 markAssertion-Reason
2. In the given figure, identify the trophic level having maximum concentration of harmful chemicals. 1 (A) T1 (B) T5 (C) T4 (D) T3
   Board 20261 markMCQ
3. Which of the following group is not ·biodegradable' ? (A) Vegetable peels, dead leaves, paper (B) Cow dung, leather bag, water (C) Polythene bag, rubber band, ball pen (D) Paper, fruits, bones Page 5 of 24 , (A) R (R) R f 1 (A), (B), (C) (D) : (A)(A) (R)(R), A…
   Board 20261 markAssertion-Reason
4. Given below is a pyramid showing various trophic levels in an ecosystem : 1V Tertiary consumers (ii) Secondary consumers (i) Primary consumers (i) Producers (a) From the organisms listed below, identify which one is to be placed at which trophic level ? Deer, …
   Board 20261 markMCQ
5. Assertion (A) : There are generally a greater number of individuals at the lower trophic levels of an ecosystem. Reason (R) : The greatest number is of the producers.
   Board 20261 markAssertion-Reason
6. “Variation is useful for the survival of species over time.” Explain this statement with the help of an example.
   Board 20261 markvery short
7. The percentage of solar energy which is not converted into food energy by the leaves of green plants in a terrestrial ecosystem is about : (A) 1% (B) 10% (C) 90% (D) 99%.
   Board 20251 markAssertion-Reason
8. Which of the following groups do not constitute a food chain ? (i) Wolf, rabbit, grass, lion (ii) Plankton, man, grasshopper, fish (iii) Hawk, grass, snake, grasshopper, frog (iv) Grass, snake, wolf, tiger (A) (i) and (iv) (B) (i) and (iii) (C) (ii) and (iii) …
   Board 20251 markMCQ
9. ‘‘Excessive use of chemicals and pesticides in agriculture adversely effect the environment.’’ Justify this statement.
   Board 20252 marksshort answer
10. Assertion (A) : The amount of ozone in the atmosphere began to drop sharply in the 1980s. Reason (R) : The oxygen atoms combine with molecular oxygen to form ozone.
    Board 20251 markAssertion-Reason
11. Assertion (A) : Accumulation of harmful chemicals is maximum in the organisms at the highest trophic level of a food chain. Reason (R) : Harmful chemicals are sprayed on the crops to protect them from diseases and pests. 11 RUT (R) : RUT (R) : 21. (i) (i) (i) …
    Board 20241 markAssertion-Reason
12. Identify the food chain in which the organisms of the second trophic level are missing : (a) Grass, goat, lion (b) Zooplankton, Phytoplankton, small fish, large fish (c) Tiger, grass, snake, frog (d) Grasshopper, grass, snake, frog, eagle
    Board 20241 markMCQ
13. (A) Plants · Deer · Lion In the given food chain, what will be the impact of removing all the organisms of second trophic level on the first and third trophic level? Will the impact be the same for the organisms of the third trophic level in the above food cha…
    Board 20243 marksshort answer
14. Use of pesticides to protect our crops affect organisms at various trophic levels especially human beings. Name the phenomenon involved and explain how does it happen. 17 1 98 34. (a) (i) (ii) (ii·(C,2) (b) (i) 34. (ii) (1) (2) (3) (4) 35. (i) (a) (ii) (1) (2)…
    Board 20243 marksshort answer
15. How do harmful chemicals get accumulated progressively at each trophic level in a food chain? 19 -+ - 27. (a) (i) 4NH, + 50, · 4NO + 6H,0 (ii) H,O + F² ·HF +HOF (iii) Fe,O, + 3CO · 2Fe + 3CO2 (iv) 2H, +0,·2H,0 (b) 28. (a) (b) 29. (i) (a) (ii) (b) (i) (ii) - h …
    Board 20232 marksshort answer
16. Explain how some harmful chemicals enter our bodies through the food chain. Why is the concentration of these harmful chemicals found to be maximum in human beings ?
    Board 20233 marksshort answer
17. (a) (i) Why does a kitchen garden called an artificial ecosystem while a forest is considered to be a natural ecosystem ? (ii) While designing an artificial ecosystem at home, write any two things to be kept in mind to convert it into a self-sustaining system.…
    Board 20233 marksshort answer
18. (a) What is ozone ? How is it formed in the upper layers of the E atmosphere ? How does ozone affect our ecosystem ? 2 OR (b) (i) List two human-made ecosystems. 1 (ii) nt. 1 IÊS> I
    Board 20221 markvery short
19. In the following food chain, only 2J of energy was available to the peacocks. How much energy would have been present in Grass ? Justify youranswer. GRASS·GRASSHOPPER-·FROG·SNAKE·PEACOCK OR (a) What is meant by garbage ? List two classes into which garbage is …
    Board 20221 markMCQ
20. (a) We do not clean ponds or lakes, but an aquarium needs to be cleaned regularly. Why ? 1+2 (b) Why is ozone layer getting depleted at the higher levels of the atmosphere?Mention one harmful effect caused by its depletion.
    Board 20221 markvery short

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