What do these two changes have in common?
newly poured concrete becoming hard
a copper statue turning green

 - Both are caused by heating.
 - Both are chemical changes.
 - Both are only physical changes.
 - Both are caused by cooling.
Step 1: Think about each change.
Concrete hardening is a chemical change. The chemicals in the concrete react with each other to form a different type of matter. The new matter is hard and strong.
A copper statue turning green is a chemical change. The copper reacts with oxygen in the air. This reaction forms a different type of matter called copper oxide. The copper oxide is green.
Step 2: Look at each answer choice.
Both are only physical changes.
Both changes are chemical changes. They are not physical changes.
Both are chemical changes.
Both changes are chemical changes. The type of matter before and after each change is different.
Both are caused by heating.
Neither change is caused by heating.
Both are caused by cooling.
Neither change is caused by cooling.