Biological processes that systematically vary over a 24-hour cycle are called _____ and are regulated by a cluster of neurons called the _____.
A) intrinsic rhythms; melatonin cluster
B) circadian rhythms; suprachiasmatic nucleus
C) circadian rhythms; pineal gland
D) brain waves; suprachiasmatic nucleus

Question

Quizplus · Accepted Answer

Circadian rhythms are biological processes that vary over a 24-hour cycle, and they are regulated by a cluster of neurons called the suprachiasmatic nucleus (SCN) located in the hypothalamus of the brain. The pineal gland does secrete the hormone melatonin, but it is not responsible for regulating circadian rhythms. Brain waves are not biological processes that vary over a 24-hour cycle.

Biological Processes That Systematically Vary Over a 24-Hour Cycle Are