From which stage of sleep is it most difficult to be awakened?

Name: From which stage of sleep is it most difficult to be awakened?
Brand: Quizplus
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Question

Quizplus · Accepted Answer

It is most difficult to be awakened during Stage IV sleep, also known as deep sleep or slow-wave sleep. During this stage, the brain waves slow down significantly and it is when the body is most relaxed and restoration occurs. It is also the stage where sleepwalking, night terrors, and bedwetting can occur.

From Which Stage of Sleep Is It Most Difficult to Be