People and most other animals wake up and go to sleep on a regular basis, at about the same time every 24 hours. What causes this 24-hour cycle?

Question

Quizplus · Accepted Answer

The 24-hour cycle, also known as the circadian rhythm, is generated by a built-in mechanism within each individual. This mechanism is regulated by internal biological clocks, particularly the suprachiasmatic nucleus (SCN) in the brain. While light and darkness cues can influence the circadian rhythm, the mechanism itself is inherent in each individual. Therefore, choice C is the best answer.

People and Most Other Animals Wake Up and Go to Sleep