At 3 o'clock in the morning,John has already slept for four hours.As long as his sleep continues,we can expect an increasing occurrence of
A) hypnagogic sensations.
B) muscle tension.
C) REM (R)sleep.
D) N3 sleep.

Question

Quizplus · Accepted Answer

As we sleep through the night, we cycle through stages of non-REM and REM sleep. The first period of REM sleep usually occurs around 90 minutes after falling asleep, and then recurs at regular intervals throughout the night, with each subsequent period of REM sleep growing longer. Since John has been sleeping for 4 hours already, it is likely that he has already experienced several cycles of non-REM and REM sleep, and is currently in a period of REM sleep, making choice C the best option.

At 3 O'clock in the Morning,John Has Already Slept for Four