What do these two changes have in common?
chemicals in a battery reacting to power a flashlight
an old sandwich rotting in a trashcan

 - Both are chemical changes.
 - Both are only physical changes.
 - Both are caused by cooling.
 - Both are caused by heating.
Step 1: Think about each change.
Chemicals in a battery reacting to power a flashlight is a chemical change. When the flashlight is turned on, the chemicals in the battery react with each other to form new chemicals. This creates electricity, which powers the lightbulb.
A sandwich rotting is a chemical change. The matter in the sandwich breaks down and slowly turns into a different type 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.
Neither change is caused by heating.
Both are caused by cooling.
Neither change is caused by cooling.