Part 1 of Essay
As fundamental as drinking or eating, sleeping can be described as a certain necessity that all animals need. Although it can not be proven beyond the shadow of a doubt what the evolutionary advantages are, there have been many studies that show what happens if we do not sleep. These slight changes in behavior can be ver ....

Part 2 of Essay
.... waves are huge and slow which makes this stage the hardest to wake from. After an hour or so, you shift into a highly active stage characterized by rapid eye movements, hence the name REM sleep. Suddenly your brain waves are almost the same as if you were awake. You're in the dreaming stage, which occurs several times across the course of the night. Now, what happens when we're deprived of the restful sleep we need? We're less alert and attentive, more inclined to irritability and other mood problems ....