A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. Molecules are made up of atom s that are held together by chemical bonds.
Some studies have shown that your deep sleep should at least be 20% of your overall sleep. It means that since most adults need 8-9 hours of sleep, they will need about 1.6-1.8 hours of deep sleep to feel fully functional next day. However, the time of deep sleep is changed and that's mainly due to the change in the sleep need of different group of people. For instance: Age Group.
Sleep: 16-18 hours a day are spent sleeping. Half is in REM sleep and the other is Deep sleep. REM sleep is when we dream. It is when the best sleep occurs and it is truly necessary to function. Auto-Stimulation Hypothesis - REM sleep is necessary Other states consist of Drowsiness, Quiet Alertness, and Crying.