What happens mostly when someone goes to sleep is that the conscious mind is less active than the unconscious mind. The answer to this question is C) As sleep progresses, Stage 3 and Stage 4 sleep diminish while REM sleep increases.
In a typical night's sleep, Stage 3 and Stage 4 is known as the deep sleep wherein the person is less responsive to the outside world or to the surroundings. In deep sleep, there is no eye movement or muscle activity. These occur mostly half of the night's sleep. The other half is the REM sleep.
REM sleep is where our nervous system is highly active, while our voluntary muscles hardly move and this is where dreams occur.
