Biological clocks are organisms’ natural timing devices. There are several such biological clocks, which are controlled by a master clock in the brain – SCN (suprachiasmatic nucleus).

Many physiological processes in our body are controlled by the biological clock and show circadian rhythmicity. ( Appear at regular time in the day – 24 hours)

Biological rhythm (BR) is a phrase often used interchangeably with circadian rhythm. These rhythms are a series of bodily functions (physical processes) regulated by the body’s internal clock. They control cycles like sleep and wakefulness, body temperature, hormone secretion, and more.