Question

select the correct answer.
which of the following is a chemical reaction?
a. breaking a glass pane
b. freezing water
c. digestion of food
d. cutting down a tree
e. evaporation of rubbing alcohol

Explanation:

A chemical reaction produces new substances with different chemical compositions. Options A, B, D, and E are physical changes (no new substances form: glass remains glass, water remains H₂O in solid form, wood remains wood, rubbing alcohol remains the same chemical just as vapor). Digestion breaks down food molecules (like complex carbs into glucose) into new chemical substances, so it is a chemical reaction.

Answer:

C. digestion of food