What do these two changes have in common?
mixing sand and gravel
water evaporating from a lake

 - Both are only physical changes.
 - Both are chemical changes.
 - Both are caused by cooling.
 - Both are caused by heating.
Step 1: Think about each change.
Mixing sand and gravel is a physical change. Together, the sand and gravel make a mixture. But making this mixture does not form a different type of matter.
Water evaporating from a lake is a change of state. So, it is a physical change. The liquid changes into a gas, but 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.
Water evaporating is caused by heating. But mixing sand and gravel is not.
Both are caused by cooling.
Neither change is caused by cooling.