A stage of sleep characterized by almost pure delta waves, and our most restful sleep... A. Stage I
B. Stage III
C. Stage IV
D. Stage V (REM)

Stage III

Explanation:

Not stage 1, as you can wake up easily once you enter it

Not stage 2, as you're preparing for deep sleep

Stage 3, this is your deep sleep, your body repairs tissues at this stage

Not Rem, as rem fastens your heartbeat, you're brain is also very active in the rem stage

between the two muscle layers is the myenteric or auerbach's plexus, which controls peristalsis. in the colon, the muscularis externa is much thicker because the feces are large and heavy, requiring more force to push along. the stomach has a third layer of muscularis externa: the inner oblique layer.

not meh

explanation: