Final answer:
The basic rest-activity cycle (BRAC) is a daily rhythm that alternates between periods of rest and activity. It is regulated by the circadian and homeostatic mechanisms that regulate sleep.
Step-by-step explanation:
The basic rest-activity cycle (BRAC) is a biological rhythm that refers to the cyclical pattern of rest and activity that occurs in organisms. It is a daily rhythm that alternates between periods of rest and periods of activity.
For example, in humans, the BRAC is often associated with the sleep-wake cycle. During the rest phase, the body is in a state of reduced physical activity and sensory awareness, and sleep occurs. During the activity phase, the body is awake and engaged in various activities.
This cycle is regulated by the circadian and homeostatic mechanisms that regulate sleep. The circadian mechanism is influenced by internal biological clocks and external cues such as light and darkness. The homeostatic mechanism is influenced by the body's need for sleep, which increases after periods of sleep deprivation.