What do these two changes have in common?
making jam
a slice of banana turning brown

 - Both are caused by heating.
 - Both are caused by cooling.
 - Both are only physical changes.
 - Both are chemical changes.
Step 1: Think about each change.
Making jam is a chemical change. It involves mixing fruit, sugar, and a substance called pectin.
When these ingredients are mixed and cooked, the chemical bonds in their molecules are broken. The atoms then link together to form different molecules that make up the jam.
A slice of banana turning brown is a chemical change. The part of the banana in contact with the air reacts with oxygen and 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.
The reaction that makes jam is caused by heating. But a slice of banana turning brown is not.
Both are caused by cooling.
Neither change is caused by cooling.