Question

what do these two changes have in common? a piece of pear turning brown a copper statue turning green select all that apply. both are only physical changes. both are caused by heating. both are caused by cooling. both are chemical changes.

Explanation:

A piece of pear turning brown is due to oxidation (a chemical reaction with oxygen in the air). A copper statue turning green is due to a chemical reaction between copper, oxygen, water, and carbon - dioxide in the air, forming copper carbonate and other compounds. Both involve chemical reactions that change the chemical composition of the substances.

Answer:

Both are chemical changes.