A hamster, when put in endless darkness, will display activity that fits a 23-hour day. This rhythm that the hamster is displaying is a(n)
A) endogenous rhythm.
B) pacemaker.
C) entrained rhythm.
D) internal rhythm.
E) external rhythm.

Question

Quizplus · Accepted Answer

The hamster's behavior in constant darkness suggests that it has an endogenous rhythm, meaning that it has an internal biological clock that is driving its behavior rather than relying on external cues (such as light) to set its circadian rhythm.

A Hamster, When Put in Endless Darkness, Will Display Activity