Cycles of Biological Activity That are Repeated Every 24 Hours

Question

Cycles of biological activity that are repeated every 24 hours are called ____.  
A) systemic acquired rhythms
B) tropisms
C) physiological requirements
D) circadian rhythms
E) photoperiods

Accepted Answer

Circadian rhythms are biological cycles that repeat every 24 hours. These rhythms are important for regulating processes such as sleep-wake cycles, hormone production, and metabolism. Examples of circadian rhythms include the sleep-wake cycle and the release of cortisol from the adrenal gland.