What connection can be made between stages 3 and 4 of sleep and the brain's activity during these stages?

the first text happens in 4 ... and under is text 3.

Explanation:

It is called slow wave sleep because the brain waves slow to what are known as delta waves with the occasional faster wave. As the body moves from stage three to stage four, the number of delta waves increase and the faster waves decrease ... During slow wave sleep there is no eye movement, and the body becomes immobile.

Stage 3 non-REM sleep is the period of deep sleep that you need to feel refreshed in the morning. It occurs in longer periods during the first half of the night. Your heartbeat and breathing slow to their lowest levels during sleep. Your muscles are relaxed and it may be difficult to awaken you.