Question

What are zeitgebers?

1) Cellular mechanisms that serve as internal biological clocks
2) Free-running biological clocks
3) Fluctuations in physiological functions with circadian rhythms
4) Environmental cues that help biological clocks become entrained to the day-night cycle and the 24-hour day

Answer 1

Zeitgebers are environmental cues that help biological clocks become entrained to the day-night cycle and the 24-hour day.

Step-by-step explanation:

Zeitgebers are environmental cues that help biological clocks become entrained to the day-night cycle and the 24-hour day. In many species, including humans, circadian rhythms are controlled by a tiny structure called the biological clock located in a gland at the base of the brain.

The biological clock sends signals to the body, causing regular changes in behavior and body processes. The amount of light entering the eyes helps control the biological clock, resulting in changes that repeat every 24 hours.