Community is a group of independent and interacting population of

$A$ kind of similarity found in polar regions and high altitudes is

Explain how ecology is related to an organism?

$A$ 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 $D$.

Consider the following four conditions $(i-iv)$ and select the pair that represents the adaptation of desert lizards to their environment.
$(i)$ Burrowing into the soil to escape high temperatures.
$(ii)$ Rapidly losing body heat during high temperatures.
$(iii)$ Basking in the sun and absorbing heat when the temperature is low.
$(iv)$ Insulating the body due to a thick layer of fat.

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