The endogenous nature of biological rhythms is based on the observations that animals isolated from light and dark cues
A) continue to have cycles of exactly 24 hours' duration.
B) continue to have cycles of approximately 24 hours' duration; some more rapid, some slower.
C) synchronize activity with whatever lighting cycle is imposed on them.
D) cease having any rhythms.
E) are independent of any genetic determinants.

Question

Quizplus · Accepted Answer

When animals are isolated from light and dark cues, they continue to have cycles of approximately 24 hours' duration, but these cycles may vary slightly from animal to animal, with some more rapid and some slower. This supports the idea that biological rhythms are endogenous, or internally driven, rather than solely dependent on external cues.

The Endogenous Nature of Biological Rhythms Is Based on the Observations