What do these two changes have in common?
burning food on a stove
grilling a hamburger

 - Both are only physical changes.
 - Both are caused by heating.
 - Both are caused by cooling.
Step 1: Think about each change.
Burning food on a stove is a chemical change. When the food burns, the type of matter in it changes. The food turns black and gives off smoke.
Grilling a hamburger is a chemical change. Heat from the grill causes the matter in the meat to change. Cooked meat and raw meat are different types of matter.
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.