The biological perspective views behavior and mental processes as ultimately resulting from physiological and genetic factors. Key concepts include localization of brain function, with different areas controlling processes like speech, vision, and hearing. The brain is also lateralized, with the left and right hemispheres specialized for different tasks. Biological rhythms like the circadian rhythm regulate sleep-wake cycles through mechanisms like the body clock and the pineal gland. Theories of sleep propose functions like restoration, memory consolidation, and energy conservation from an evolutionary perspective. Dreaming may aid in clearing useless memories according to some theories.