What is one of the functions of the parasympathetic nervous system?

The parasympathetic nervous system plays a crucial role in maintaining the body's homeostasis and promoting a state of relaxation. One of its primary functions is to stimulate digestive activity. This is accomplished by increasing blood flow to the digestive organs, stimulating the production of digestive enzymes, and promoting peristalsis, which is the coordinated contraction of muscles in the digestive tract that moves food through the system. This system counterbalances the sympathetic nervous system, which is responsible for the body's fight or flight response, thereby ensuring that the body can rest, recuperate, and efficiently process nutrients.

In contrast, the other options pertain more closely to the functions of the sympathetic nervous system: enhancing the fight or flight response, increasing blood pressure, and mobilizing energy are all actions taken to prepare the body for stress or emergency situations. These are not functions of the parasympathetic nervous system, which instead facilitates recovery and nourishment.