What do these two changes have in common?
rust forming on a metal gate
making jam

 - Both are caused by cooling.
 - Both are chemical changes.
 - Both are caused by heating.
 - Both are only physical changes.
Step 1: Think about each change.
Rust forming on a metal gate is a chemical change. As the gate rusts, the metal turns into a different type of matter called rust. Rust is reddish-brown and falls apart easily.
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.
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 rust forming on a metal gate is not.
Both are caused by cooling.
Neither change is caused by cooling.