Given below are two statements, one is labelled as Assertion (A) and other as Reason (R): Assertion (A): Various components of an ecosystem are not interdependent. Reason (R): Human activities have the impacts on the environment. Select the correct answer using the codes given below. Codes:
- (a)Both (A) and (R) are true and (R) is correct explanation of (A)
- (b)Both (A) and (R) are true, but (R) is not correct explanation of (A)
- (c)(A) is true, but (R) is false
- (d)(A) is false, but (R) is true
Correct — D, (A) is false but (R) is true. The Assertion is FALSE: the components of an ecosystem — producers, consumers, decomposers and the abiotic environment — are deeply INTER-dependent; energy flow and nutrient cycling link them together, and a change in one component affects the others. The Reason is TRUE: human activities (deforestation, pollution, land-use change, emissions) do have real impacts on the environment. Since a false assertion is paired with a true reason, the answer is option (d).
- (a)Both (A) and (R) are true and (R) is correct explanation of (A) — Wrong — (A) is not true. Ecosystem components ARE interdependent, so (A) cannot be accepted as true.
- (b)Both (A) and (R) are true, but (R) is not correct explanation of (A) — Wrong — again this treats (A) as true. The claim that ecosystem components are 'not interdependent' is factually incorrect.
- (c)(A) is true, but (R) is false — Wrong on both counts — (A) is false (components are interdependent) and (R) is true (human activities do affect the environment).
An ecosystem is a functional unit in which biotic components (producers, consumers, decomposers) and abiotic components (soil, water, air, sunlight, temperature) interact. These parts are mutually dependent: producers fix energy that flows to consumers and then decomposers, while decomposers recycle nutrients back to the abiotic pool. Because everything is linked through energy flow and biogeochemical cycles, disturbing one component ripples through the whole system.
In assertion–reason items, test each statement's truth first. Here the Assertion contains the word 'not', which flips a true idea (components ARE interdependent) into a false one — a classic trap. The Reason, a separate and independently true fact, then forces the (A) false / (R) true pattern, i.e. option (d). The Reason is not even a candidate explanation, because a false assertion cannot be 'explained'.
- Ecosystem = interacting biotic + abiotic components — they ARE interdependent (so Assertion is false).
- Interdependence works through energy flow (food chains/webs) and nutrient (biogeochemical) cycling.
- Human activities (pollution, deforestation, emissions) do impact the environment (Reason is true).
- A false Assertion with a true Reason gives code (d).
The word 'not' makes the Assertion false; the Reason is independently true → code (d).
- Missing the negation ('not interdependent') and wrongly reading the Assertion as true.
- Trying to judge whether R 'explains' A before checking that A is even true.
UPPSC/UPSC frequently plant a negation inside the Assertion so a true concept reads as false — always resolve each statement's truth value before comparing them.
No directly related past PYQ was found.
- practice — not a real PYQ
Which of the following is an abiotic component of an ecosystem?
- (a)Decomposers
- (b)Producers
- (c)Temperature
- (d)Herbivores
Answer(c) Temperature — a physical (abiotic) factor; the others are biotic components.
- practice — not a real PYQ
In an ecosystem, decomposers are important because they:
- (a)Fix atmospheric nitrogen directly into plants
- (b)Recycle nutrients from dead matter back to the abiotic pool
- (c)Convert sunlight into chemical energy
- (d)Occupy the highest trophic level
Answer(b) Recycle nutrients back to the environment — closing the nutrient cycle and linking biotic and abiotic components.