Question

which of these changes is a chemical change?
water freezing
glass breaking
mixing sand and water
food digesting

Explanation:

A chemical change results in a new substance being formed. Water freezing is a physical change (change of state). Glass breaking is a physical change (change in shape). Mixing sand and water is a physical change (no new substance formed). Food digesting involves chemical reactions where enzymes break down food into new substances.

Answer:

food digesting