The division of the autonomic nervous system is said to function during "rest and digest."

The answer is the parasympathetic nervous system. It is out of the three divisions of the autonomic nervous system, the others being the enteric nervous system and sympathetic nervous system. The autonomic nervous system is in control for regulating the body's unconscious actions. It is also in charge for stimulation of "rest-and-digest" or "feed and breed” activities that happen when the body is at break, particularly after eating, including sexual arousal, lacrimation (tears), salivation, urination, digestion and defecation. Its act is labelled as being opposite to that of the sympathetic nervous system, which is in control for stimulating activities associated with the fight-or-flight response.

"a.) well–developed vascular system."