Question

Assertion : Small sized animals are rarely found in polar regions.
Reason : Small sized animals have larger surface area relative to their volume and they have to spend much energy to generate body heat through metabolism.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

Thermoregulation is an energetically expensive process for many organisms. Heat loss or heat gain is a function of surface area. Small sized animals (such as shrews, humming birds etc.), have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; thus they have to expend much energy to generate body heat through metabolism. This is the main reason why very small animals are rarely found in polar regions.