Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: As food is pushed through the GI tract by peristalsis, it undergoes digestion. Digestion is the process of breaking down food into nutrients. There are two types of digestion: mechanical digestion and chemical digestion. Answer: digestion
The process of breaking down food into nutrients is known as __________