The chemical process animals use to break down nutrients into a form that can be used by the body is called digestion.

Digestion involves several steps:

1. Mechanical breakdown: Chewing, grinding, and churning break down large food particles into smaller ones.

2. Chemical breakdown: Enzymes, which are biological catalysts, break down complex molecules (proteins, carbohydrates, fats) into simpler molecules that can be absorbed by the body.

3. Absorption: The broken-down nutrients are absorbed into the bloodstream through the small intestine.

4. Elimination: Undigested waste is eliminated from the body.

So, digestion is a complex process that involves both mechanical and chemical processes to ensure that the nutrients in our food can be used by our cells to provide energy and build new tissues.