Answer:
REM Stage of Sleep
Explanation:
Stage 3 Sleep [ REM Stage ] is the deepest stage of sleep. It is most revitalising & refreshening up sleep. It is crucial to re energise brain.
In this stage : Respiration , heart rate increases, brain activity is high & vivid dreams may occur, body becomes immobile & it is difficult to wake someone up. There are slow delta waves & rapid eye movement.
It is a very short duration (3 - 8% ) of total sleep and its concentration keeps on decreasing with age.
