+A biological clock is an innate time-keeping system present in most living organisms. These internal rhythms regulate nearly all aspects of [Life](/wiki/life), from sleep-wake cycles to [Hormone](/wiki/hormone) release, adapting organisms to Earth's daily and seasonal changes.
+## See also
+- [Circadian Rhythm](/wiki/circadian_rhythm)
+- [Chronobiology](/wiki/chronobiology)
+- [Sleep](/wiki/sleep)
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