Why Are Humans Typically Able to Remain in the Bed

Multiple Choice

Why are humans typically able to remain in the bed during sleep?

A) Your brain signals the body to become paralyzed during the night so you don't move off the bed.
B) The brain is still processing information about its surroundings, thus you are aware of the boundaries of the bed.
C) You are consciously aware of the bed's boundaries at all times during sleep.
D) Most people typically fall out of bed, but because they are unaware of it they don't report it.