The factors that direct and energize the behavior of humans and other organisms are known as MOTIVATION.

According to the facial-affect program hypothesis, a set of nerve impulses make the face display the appropriate expression.

Consciousness is the awareness of the sensations, thoughts, and feelings being experienced at a given moment.

A lack of some basic biological requirement such as water, which produces a drive to obtain that requirement (thirst), is known as the drive-reduction approach.