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Science · 2022 · 3 marks
CBSE 2022 · Region 1 · Set 1 · Q13
(a) Name the group of organisms which form in the first trophic level of all food chains. Why are they called so? (b) Why are the human beings most…
(a)
Name the group of organisms which form in the first trophic level of all food chains. Why are they called so?
(b)
Why are the human beings most adversely affected by bio-magnification?
(c)
State one ill-effect of the absence of decomposers from a natural ecosystem.
Marking-scheme solution
(a) Producers, as they can manufacture food by the process of photosynthesis.
(b) When non-degradable harmful chemicals (pesticides / DDT, etc.) enter a food chain, they get progressively accumulated at each trophic level. Human beings occupy the top level in any food chain, therefore the maximum concentration of these chemicals get accumulated in their bodies.
(c) Ill effects of absence of decomposers from natural ecosystem :
(i) Earth would be covered with dead bodies & foul smell
(ii) Recycling of minerals will not take place
(iii) Soil will not get replenished
(iv) Ecosystem will get disrupted
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CBSE Class 10 Science past-paper question from the 2022 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.