Periods of REM sleep alternate with periods of non-REM sleep in a cycle that recurs about every _______________ minutes or so.
A)30
B)90
C)150
D)210

Question

Quizplus · Accepted Answer

The correct answer is 90. The sleep cycle is approximately 90 minutes long, with periods of REM sleep occurring every 90 minutes or so. Non-REM sleep usually occurs during the first part of the cycle, and REM sleep occurs during the latter part of the cycle. This pattern repeats throughout the night, with the length of REM sleep increasing in each successive cycle.

Periods of REM Sleep Alternate with Periods of Non-REM Sleep