Sleep.
It is a mechanism most organisms cannot do without.
As a natural and ubiquitous physiological phenomenon, for most organisms, it is not only necessary but also a critical factor in maintaining health.
From single-celled organisms to complex multicellular organisms, including humans, almost all forms of life undergo some form of rest or dormancy.
This special state of reduced or even temporarily halted activity has many important functions for organisms.
Among animals, the expressions of deep sleep vary, from nocturnal sleep to seasonal hibernation patterns, all adapted to environmental changes.
For example, many mammals enter a prolonged state of hibernation during the food-scarce winter months, reducing their metabolic rate to save energy.
For humans and other diurnal animals, nocturnal sleep is a more regular form of deep sleep. It helps repair damaged tissues, consolidate memories, regulate emotions, and rebalance hormone levels.
