During REM sleep,

A) the brain is less active than at any other time.
B) heart rate and breathing rate are low and steady.
C) the muscles are tense and active.
D) dreaming is likely to occur.

Brain Activity

Brain activity involves the various neurological processes and actions carried out by the brain, including cognitive functions, emotions, and controlling bodily functions.

Heart Rate

The frequency of cardiac contractions, often quantified as the number of beats occurring every minute.

Breathing Rate

The number of breaths taken per minute, an important vital sign reflecting respiratory health and metabolic demand.