Given below are two statements, one is labelled asAssertion (A) :and other as Reason (R):Assertion (A):Various components of an ecosystem are not interdependent.Reason (R):Human activities have impacts on the environment.Select the correct answer using the codes given below.

1. A

   Both (A) and (R) are true and (R) is the correct explanation of (A).

   (a) Both true and R explains A. Assertion is false: ecosystem parts are interdependent, so this double-true-and-explains reading cannot stand.

2. B

   Both (A) and (R) are true, but (R) is not the correct explanation of (A).

   (b) Both true but R does not explain A. Again both cannot be true because A is false.

3. C

   (A) is true, but (R) is false.

   (c) A true, R false. That flips the facts: A is the false limb; R is a true statement about human impact.

4. D

   (A) is false, but (R) is true.

   (d) A is false, but R is true. Producers, consumers and decomposers, plus abiotic factors, are tightly interdependent; saying they are not is false. Human activities—pollution, land-use change, overharvest—do alter the environment, so R is true. R does not have to explain a false A. That combination is the official key.

Summary. Official key is (d) (A) is false, but (R) is true. An ecosystem is a web of dependence among biotic and abiotic parts. The assertion denies that dependence and therefore falls. The reason correctly notes anthropogenic environmental impact. True R cannot rescue false A, and it is not offered as an explanation of A on this code.