The muscularis externa propels materials from one portion of the digestive tract to the other by a series of wavelike contractions called peristalsis, while in most areas of the small intestine movements churn and fragment digestive materials.

The given question is incorrect. The correct question is as follows:

The muscularis externa propels materials from one portion of the digestive tract to the other by a series of wavelike contractions called peristalsis, while in most areas of the small intestine movements churn and fragment digestive materials.

Segmentation.

Explanation:

Digestion is the biological process that helps in the breakdown of the large food particles like carbohydrates, proteins into the small substances that are directly absorbed by the body for the production of energy.

The peristalsis movement occurs in the esophagus and other parts of the digestive system for the food propagation. The segmentation movement with the help of muscles also occurs especially in the small intestine for the proper mixing of the food and absorption by the body.

Thus, the correct answer is segmentation.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.