What does $Allen's$ rule represent?

Which one of the following correctly represents an organism and its ecological niche?

Provide information about the natural habitats of organisms.

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?

Relative to roots, the shoots are massive in plants of

$A$ characteristic which enables an organism to live in an environment is called