What do these two changes have in common?
butter melting on a hot day
burning a marshmallow over a campfire

 - Both are caused by cooling.
 - Both are caused by heating.
 - Both are only physical changes.
 - Both are chemical changes.
Step 1: Think about each change.
Butter melting on a hot day is a change of state. So, it is a physical change. The butter changes from solid to liquid, but it is still made of the same type of matter.
Burning a marshmallow is a chemical change. The heat from the fire causes the type of matter in the marshmallow to change. The marshmallow becomes black and crispy.
Step 2: Look at each answer choice.
Both are only physical changes.
Butter melting on a hot day is a physical change. But burning a marshmallow is not.
Both are chemical changes.
Burning a marshmallow is a chemical change. But butter melting on a hot day is not.
Both are caused by heating.
Both changes are caused by heating.
Both are caused by cooling.
Neither change is caused by cooling.