Given below are two statements:

Assertion (A): Small animals have a larger surface area relative to their volume.

Reason (R): They lose body heat when it’s cold outside.

Choose the correct answer:

Conceptual BreakdownAssertion (A) is True:This is a mathematical and biological principle. As an object (or animal) decreases in size, its surface area-to-volume ratio ($SA:V$) increases. For example, a small shrew has much more skin surface relative to its internal body mass than an elephant does.Reason (R) is True:Because small animals have a high $SA:V$ ratio, they have more surface (skin) through which heat can escape. Consequently, they lose body heat very rapidly in cold environments. This is why you rarely find very small endothermic (warm-blooded) animals in extremely cold polar regions—they would have to eat constantly just to maintain their body temperature.Why (R) is NOT the explanation for (A):The Reason (R) describes a consequence of the Assertion, not the cause. The cause of Assertion (A) is geometric scaling, not heat loss. If the question asked, "Small animals tend to struggle in cold climates because they have a large surface area relative to their volume," then the logic would follow. Here, the heat loss doesn't cause them to have a large surface area; the large surface area causes the heat loss.