What do these two changes have in common?
rust forming on a metal gate
burning a candle

 - Both are chemical changes.
 - Both are caused by heating.
 - Both are only physical changes.
 - Both are caused by cooling.
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.
Burning a candle is a chemical change. Both the wick and the melted wax burn. They react with oxygen in the air and turn into soot, carbon dioxide, and water.
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.
Burning is caused by heating. But rust forming on a metal gate is not.
Both are caused by cooling.
Neither change is caused by cooling.