Air is filtered, warmed, and moistened in the
a. nose and mouth.
c. lungs.
b. throat.
d. pharynx.

The correct answer is that it is warmed and moistened already in nose and mouth, at the very beginning, when it enters our body (answer a).

It needs to be filtered and warmed alredy before it enters further, because our internal organs are delicate and a dry, dirty air would cause damage to our lungs and other organs.

Cells of an organism tell each other when predators are near.