Answer:
A circadian rhythm that is out of sync
Step-by-step explanation:
Social jet lag is primarily caused by a circadian rhythm that is out of sync with an individual's social or work schedule. It occurs when an individual's internal biological clock, which regulates sleep-wake patterns and other physiological processes, is misaligned with their daily activities and commitments. This misalignment can lead to symptoms similar to jet lag, such as fatigue, poor concentration, and difficulty sleeping. Restless leg syndrome, overactive homeostatic sleep drive, and the specific stages of slow-wave sleep are not the primary causes of social jet lag.