The process of digestion begins as soon as you take a bite of food. In the mouth, the teeth chew and grind food into smaller pieces. At the same time, enzymes in saliva begin chemically digesting food. When food has become a soft pulp, called bolus, the tongue pushes it to the back of the mouth. After it has been swallowed, the bolus moves to the esophagus. Layers of muscle in the esophagus contract and expand, pushing food down in a process called peristalsis. Peristalsis allows food to move down the esophagus when we are lying down—or even upside-down!

Question

The process of digestion begins as soon as you take a bite of food. In the mouth, the teeth chew and grind food into smaller pieces. At the same time, enzymes in saliva begin chemically digesting food. When food has become a soft pulp, called bolus, the tongue pushes it to the back of the mouth. After it has been swallowed, the bolus moves to the esophagus. Layers of muscle in the esophagus contract and expand, pushing food down in a process called peristalsis. Peristalsis allows food to move down the esophagus when we are lying down—or even upside-down!

Which of these is true about peristalsis?

A
It is a type of muscle.

B
It takes place in the mouth.

C
Its force is stronger than gravity.

D
It only happens when you are upside-down.

Answer 1

C

Its force is stronger than gravity.