Homeostasis: The body's tendency to maintain internal stability by adjusting its physiological processes. For example, when the body becomes too hot, it sweats to cool down and restore balance.
Drive Reduction Theory: A psychological theory that suggests motivation arises from the need to reduce internal tension caused by unmet biological needs.
Maslow's Hierarchy of Needs: A framework that categorizes human needs into five levels (physiological, safety, belongingness/love, esteem, self-actualization) where lower-level needs must be met before higher-level ones can become motivating factors.