AP Psychology Practice Test 2025 - Free AP Psychology Practice Questions and Study Guide

The main function of the parasympathetic nervous system is to calm the body and conserve energy. This division of the autonomic nervous system is often referred to as the "rest and digest" system. It is responsible for promoting a state of relaxation after a stressful event or in a non-threatening environment. When activated, the parasympathetic nervous system reduces heart rate, lowers blood pressure, and increases digestive processes, thereby helping the body to replenish resources and maintain homeostasis.

In contrast, the sympathetic nervous system, which is not the focus of this question, is the one that arouses and prepares the body for action, often referred to as the "fight or flight" response. The control of skeletal muscles pertains to the somatic nervous system, which operates differently from the autonomic nervous system. Meanwhile, the role of intervening between sensory and motor outputs is more associated with reflexes and spinal cord processing rather than the direct functions of the parasympathetic nervous system.