Question

Digestion in the body occurs chemically and mechanically. The digestive process starts in the mouth as the teeth grind the food and saliva adds digestive enzymes. The process continues in the esophagus aided by peristalsis.

In this passage, peristalsis is (2 points)

a
the addition of pepsin.
b
the absorption of lacteals.
c
the production of bile.
d
the contraction of muscle.