Physical and chemical changes occur during digestion. an example of a chemical change during digestion is. a: teeth chewing the food. b: the mouth swallowing food. c: the esophagus moving food. d: enzymes breaking down food.

It would be D. Enzymes breaking down the food. Enzymes are used to speed up chemical reactions

Option (D) is the correct answer.

Explanation:

A change that does not bring any difference in chemical composition of a substance are known as physical change.

For example, shape, size, mass, volume, density, etc of a substance are all physical properties.

Whereas a change that brings difference in chemical composition of a substance is known as chemical change.

For example, precipitation, reactivity, toxicity etc are chemical property.

During break down of food, salivary amylase breaks down starch into simple sugars. In stomach the enzyme pepsin converts protein into peptones in presence of acidic medium. Small intestine receives both intestinal and pancreatic juices (chemical substances) and the final digestion of fats, proteins and sugars occurs here.

Thus, we can conclude that example of a chemical change during digestion is enzymes breaking down food.