Which statement is true regarding the sleep needs of humans and other animals?
A) Dolphins do not sleep because they would drown.
B) Humans sleep on one side of the brain at a time which is why they are not totally unresponsive while sleeping .
C) Sunlight and darkness are external time markers that tie humans to a 24-hour sleep-waking cycle.
D) All animals need sleep.

Question

Quizplus · Accepted Answer

Sunlight and darkness serve as external cues that synchronize the sleep-wake cycle of humans (and many other organisms) to the 24-hour day-night cycle, a process regulated by the circadian rhythm.

Which Statement Is True Regarding the Sleep Needs of Humans