If the external causes are removed, the sleep-wake cycle in humans

Ans. d. Continue with cycle length of more than 24 hoursThe sleep-wakefulness cycle follows a 24-hour, or circadian rhythm, and is related to the light-dark cycle. If the external cues in the form of light and darkness are removed, the sleep-wakefulness cycle still remains circadian although it has a tendency to lengthen to 25-30 hour