Give reasons for the following:
a. Very small animals are rarely found in polar regions.
b. Mammals from colder climate generally have shorter ear and limbs.
c. Initially we feel nausea and fatigue when we reach a high altitude such as Rohtang Pass and then, gradually, we feel normal.

Explanation

a. Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside, then 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.
b. Mammals from colder climates generally have shorter ears and limbs to minimise heat loss. (This is called the Allen’s Rule.)
c. This is because in the low atmospheric pressure of high altitudes, the body does not get enough oxygen. But gradually we get acclimatised and stop experiencing altitude sickness.