Answer:
peristalsis.
Step-by-step explanation:
When the food enters the esophagus, it is in the form of a bolus. During this esophageal stage of swallowing, there are rhythmic contractions and relaxation of the circular and longitudinal layers of the muscularis of the GI tract. It is called peristalsis. This pushes the bolus downwards. Peristalsis in the esophagus is controlled by the medulla oblongata.
As the food enters the stomach, waves of peristalsis pass over the stomach every 15 to 25 seconds. The peristaltic waves in the stomach start at its body and become more intense as they reach the antrum. It moves gastric contents from the body of the stomach down into the antrum, a process known as propulsion.