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.

How is diapause different from hibernation?

Tiny free-living animals on the surface of water constitute:

$A$ regulators are able to maintain homeostasis by means which ensure constant body temperature,constant osmotic concentration,etc. All $B$ and $C$ and a very few lower vertebrate and invertebrate species are indeed capable of such regulation (thermoregulation and osmoregulation).
Evolutionary biologists believe that the 'success' of mammals is largely due to their ability to maintain a constant body $D$ and thrive whether they live in Antarctica or in the Sahara desert.
Choose the correct option for $A, B, C$ and $D$.

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

Organisms restricted to a narrow range of salinity are $- P$.
Organisms that tolerate a wide range of salinity are $- Q$.
Choose the correct option for $P$ and $Q$.
$P$ $Q$