What do these two changes have in common?
boiling sugar to make caramel
roasting a marshmallow over a campfire

 - Both are only physical changes.
 - Both are caused by cooling.
 - Both are caused by heating.
Step 1: Think about each change.
Boiling sugar to make caramel is a chemical change. The heat causes the sugar to change into a different type of matter. Unlike sugar, the new matter is brown and sticky.
Roasting a marshmallow is a chemical change. The type of matter on the outside of the marshmallow changes. As a marshmallow is roasted, it turns brown and crispy.
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.
Both changes are caused by heating.
Both are caused by cooling.
Neither change is caused by cooling.