Final answer:
Powerful peristaltic contractions in the colon, called mass movements, occur a few times each day and are responsible for propelling contents towards the rectum.
Step-by-step explanation:
Powerful peristaltic contractions that occur a few times each day in the colon are called mass movements. These contractions are responsible for moving the contents of the colon towards the rectum. Mass movements generally occur three to four times per day, commonly triggered by eating, as the distension in the stomach and digestion by-products in the small intestine stimulate the gastrocolic reflex, which increases motility in the colon. Fiber in the diet aids in both softening the stool and enhancing the strength of these contractions, contributing to the efficiency of the colon's functions.