Final answer:
The parasympathetic system is part of the nervous system, which is divided into the sympathetic and parasympathetic systems to regulate the body's involuntary physiological processes and maintain homeostasis.
Step-by-step explanation:
The parasympathetic system is a part of the nervous system. Specifically, it is one division of the autonomic nervous system, which is responsible for regulating involuntary physiological processes. The other division is the sympathetic nervous system. The parasympathetic nervous system plays a crucial role in the body’s “rest and digest” activities, functioning to conserve energy and restore the body to a state of calm after any type of stress or emergency. Homeostasis, the state of equilibrium in the body, is maintained through a balance between the sympathetic and parasympathetic systems. For example, at each target effector like the heart, dual innervation determines activity: one part of the system increases heart rate, while the other decreases it. This system also controls functions such as digestion, demonstrating its direct control over various internal organs.
The correct answer to the question regarding which part of the bodily system the parasympathetic system is a part of is A) Nervous system. This division of the nervous system ensures that, when the external environment does not present any immediate dangers, the body enters into a more restful mode, increasing the activity of the digestive system and decreasing overall bodily tension.