Which layer of the alimentary canal is responsible for segmentation and peristalsis?

Muscularis externa layer.

Explanation:

The muscularis externa layer lies adjacent to the submucosa membrane. This is the third layer of the gastro intestinal tract. The muscularis externa of the colon is thick as it carries and passes urine and feces.

Muscularis externa layer prevents the backward travelling of food. This layer is mainly responsible for the peristalsis movement of food in the gastro intestinal tract and responsible for the segmentation as well.