Final answer:
Constriction of pupils is an effect of parasympathetic activation.
Step-by-step explanation:
One effect of parasympathetic activation is constriction of pupils. When the parasympathetic nervous system is activated, the muscles in the iris of the eye contract, causing the pupils to become smaller. The effect of parasympathetic activation is essential in restoring the body to a state of calm after a fight-or-flight response has been triggered by the sympathetic nervous system. Among the various effects of parasympathetic activation on the body, one significant outcome is the constriction of pupils. This response is in line with the rest-and-digest functions of the parasympathetic nervous system, which also include slowing of the heart rate, lowering blood pressure, and stimulating digestion.