Final answer:
In the absence of environmental time cues, such as light and dark, human circadian rhythms would shift to a free-running cycle that is slightly longer than the typical 24-hour day.
Step-by-step explanation:
If you lived in a cave with no cues to indicate time, your circadian rhythms would gradually conform to a slightly longer than 24-hour day. Circadian rhythms are internal biological mechanisms that regulate the sleep-wake cycle, body temperature, blood pressure, and various other physiological functions over approximately a 24-hour period. In the absence of environmental cues, such as the cycle of sunlight and darkness, these rhythms have shown a tendency to deviate slightly from the exact 24-hour cycle.
The term 'circadian' comes from 'circa', meaning 'around', and 'diem', which means 'day'. So the innate circadian clock in humans has an inherent period that is close to, but not exactly, 24-hours. With no external time cues, people tend to shift to a rhythm known as free-running, which is the natural period of their biological clock if it isn't being reset by external signals, typically longer than 24 hours.