Final answer:
The 24-hour cycle that the human body experiences is called a circadian rhythm, comprising various biological processes including the sleep-wake cycle and is regulated by the biological clock in the brain.
Step-by-step explanation:
The roughly 24-hour cycle that your body goes through is called a circadian rhythm. This is a biological rhythm that occurs over a period of about 24 hours. Our sleep-wake cycle is an example of a circadian rhythm and is linked to the environmental light-dark cycle. This isn't the only physiological process that follows this pattern; heart rate, blood pressure, blood sugar, and body temperature are other examples. Circadian rhythms are driven by our biological clock, a mechanism in our brains that responds to the light entering our eyes. While changes like sleepiness and alertness are visible behaviors, internal processes such as melatonin release also follow this circadian pattern.