We just learned about Stage 2 - Non-REM Sleep.
Another part of sleep is Stage 3 - Non-REM Sleep, also called slow-wave sleep or deep sleep.
During this time of sleep, the human body lets out chemicals that help the body grow, and let the brain take a break.
The brain also works on organizing the memories from the day.
(from: wikipedia - neuroscience of sleep)
Kid Facts - Blast from the past: Ear Ossicles
