Question

Differences between propulsion and retropulsion

Answer 1

 propulsion is mearly the act of moving foreward whereas peristalsis are the smooth muscle contractions that cause the propulsion (of fecal matter in the intestines for example, or of the bolus down the esophagus to the stomach) 
hope this helps!

Answer 2

(a) Propulsion :-

1. The process in which food is moved through the system and involves swallowing and peristalsis.
2. Enables the food to mix with digestive juices.
3. Peristallic waves move food from one part to the other.

(b) Retropulsion :-

1. Some of the chyme is forced back up against the walls of the stomach.
2. Intense contractions cause backwardness of the food into stomach.
3. Small amounts of chyme is pushed into the duodenum , simultaneously forcing most of it back into the stomach.