What system detects the passage of time using internal and external factors?

The biological clock, often referred to in psychology and biology, plays a crucial role in regulating various physiological processes in response to time, both internal and external. This system is primarily driven by circadian rhythms, which are roughly 24-hour cycles influenced by environmental cues such as light and darkness. The biological clock helps synchronize the body's activities to the day-night cycle, regulating behaviors like sleep-wake patterns, hormonal release, and other bodily functions.

Internal factors include the body's intrinsic timing mechanisms, like genetic expressions and hormonal fluctuations, while external factors encompass environmental cues, such as light exposure and temperature variations. By integrating these cues, the biological clock maintains optimal functioning of bodily systems, aiding in processes like sleep regulation and metabolic control.

Other options refer to specific aspects of physiological and psychological functioning. The sleep cycle is focused more specifically on patterns of sleep and wakefulness rather than broader time perception. The endocrine system involves hormone regulation and secretion but does not directly manage time perception. A cognitive timer relates more to conscious awareness of time rather than the autonomic regulation and integration of internal and external rhythms, which is the hallmark of the biological clock.