Given below are two statements, one is labelled asAssertion (A) :and the other as Reason (R).Assertion (A):Evaporation of sweat from human skin dissipates body heat.Reason (R):High humidity on a hot day increases discomfort.

1. A

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

   Both true, R not explaining A. Humidity discomfort is a related weather fact; it does not explain why evaporating sweat removes body heat.

2. B

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

   (A) false. Evaporative cooling is standard physiology.

3. C

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

   (R) false. High humidity does raise discomfort.

4. D

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

   Both true and R explains A. R is true but is a consequence of reduced evaporation, not the explanation of A’s heat-loss mechanism as framed.

Summary. Official key is (a). Sweat evaporation cools the body. High humidity increases discomfort, but that is not the explanation of A.