The ecological niche of a population is a

Why do mammals of colder regions generally have shorter ears and limbs?
$I.$ To minimize their surface area to volume ratio
$II.$ To minimize heat loss
$III.$ To maximize their surface area to volume ratio
$IV.$ To maximize heat loss
Choose the correct combination from the given options:

In desert grasslands,which type of animals are relatively more abundant?

Crop plants grown in monoculture are

Read the following statements and select the option that represents the correct statements.
$(1)$ Kangaroo rats never drink water.
$(2)$ Birds undergo hibernation to escape adverse environmental conditions.
$(3)$ Thermal adaptation can be explained by Allen's Rule.
$(4)$ Opuntia possesses phylloclade for protection.

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