sugar dissolving in tea sunshine warming a sidewalk scissors cutting paper into pieces acid in the stomach digesting food
I gave my students this multiple choice question: Which describes a chemical change?

Only one answer is correct among these 4 choices:
- sugar dissolving in tea
- sunshine warming a sidewalk
- scissors cutting paper into pieces
- acid in the stomach digesting food

Could you tell me which one is correct?

acid in the stomach digesting food