What do these two changes have in common?
a sidewalk heating up in the sun
a puddle freezing into ice on a cold night

 - Both are chemical changes.
 - Both are caused by cooling.
 - Both are caused by heating.
 - Both are only physical changes.
Step 1: Think about each change.
A sidewalk heating up in the sun is a physical change. The temperature of the sidewalk goes up, but the sidewalk is still made of the same type of matter.
A puddle freezing into ice on a cold night is a change of state. So, it is a physical change. Liquid water freezes and becomes solid, but it is still made of water. A different type of matter is not formed.
Step 2: Look at each answer choice.
Both are only physical changes.
Both changes are physical changes. No new matter is created.
Both are chemical changes.
Both changes are physical changes. They are not chemical changes.
Both are caused by heating.
A sidewalk getting warm in the sun is caused by heating. But a puddle freezing is not.
Both are caused by cooling.
A puddle freezing is caused by cooling. But a sidewalk heating up in the sun is not.