Final answer:
Peristalsis in the digestive system is made possible by the arrangement of muscles in the walls of the GI tract. These muscles contract and relax in a wave-like motion, pushing food through the digestive system.
Step-by-step explanation:
Peristalsis is made possible by the arrangement of the muscles in the walls of the gastrointestinal (GI) tract. The GI tract is lined with layers of muscle, including smooth muscle and skeletal muscle, that contract and relax in a sequential wave-like motion to push food along the digestive system.
For example, in the small intestine, there is a double layer of smooth muscle, with an inner circular layer and an outer longitudinal layer. The contractions of these layers promote mechanical digestion, expose more of the food to digestive chemicals, and move the food along the canal.