Many processes occur in the digestive system. Which process is best classified as a physical change? Saliva converting the starch molecules in crackers into simple sugars
Digestive enzymes breaking down proteins into smaller fragments
Bacteria converting lactose into simple sugars in the intestines
Teeth grinding an almond into smaller pieces in the mouth

Maybe digestive enzymes breaking down proteins into smaller fragments

Explanation: I would say this is the correct answer because the protein provides nutrition to the body.

Teeth grinding an almond into smaller pieces in the mouth

Explanation:

The others all use a chemical to produce a different outcome. The teeth answer uses the teeth to make the almond smaller, its not changing the almond, it is still an almond so it would just change it physically not chemically like the others.