Although the Purpose of REM Sleep Is Still a Matter

Although the purpose of REM sleep is still a matter of debate, the authors point out that it clearly does have a purpose because people who lose REM sleep will:

A) spend more time than usual in the REM phase.
B) spend less time than usual in the REM phase.
C) eventually begin to experience hallucinations and delusions.
D) often recall dreams that are more vivid and strange than usual.