In which of the following is a thick layer of fat (blubber) found under the skin?

Consider the following four statements $(a-d)$ regarding certain desert animals like the kangaroo rat:
$(a)$ They have a dark color and high rate of reproduction and excrete solid urine.
$(b)$ They do not drink water,breathe at a slow rate to conserve water,and their body is covered with thick hair.
$(c)$ They feed on dry seeds and do not require drinking water.
$(d)$ They excrete very concentrated urine and do not use water to regulate body temperature.
Which two of the above statements are true?

The part of the earth where life exists is made up of:

$A$: Antarctic fishes have blubber to withstand sub-zero temperatures.
$R$: Blubber are proteins which allow the freezing of body fluids.

Small animals have a larger surface area relative to their volume,so 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. Which of the following explains why small animals are more easily able to climb up a rock compared to large animals?

Identify the organism based on the following characteristics:
- It has the ability to concentrate its urine.
- It meets its water requirements from internal fat oxidation.
- It is found in the American desert.