Peristalsis in the alimentary canal is caused by the: A. contraction of muscle layers B. action of digestive enzymes C. stretching of the mucosa D. closing of the epiglottis

It occurs because of contraction of the muscle layers. There are two types of muscle found in the alimentary canal; longitudinal and circular muscle, the alternating contraction of these muscles forces the bolus of food through the digestive system.