Question

the nervous system stimulates the arrector pili muscles. somatic parasympathetic afferent sympathetic dorsal

Explanation:

The sympathetic nervous system is part of the autonomic nervous system. It is responsible for the "fight - or - flight" response. One of its functions is to stimulate the arrector pili muscles. When stimulated, these muscles cause hair to stand on end (goosebumps). The somatic nervous system controls voluntary movements. The parasympathetic nervous system is for "rest - and - digest" and does not stimulate arrector pili. The afferent (sensory) nervous system transmits sensory information. The dorsal refers to a location (e.g., dorsal root of a spinal nerve) and not a functional division that stimulates these muscles.

Answer:

sympathetic