You are presented with the question "what type of vapor cooling causes that vapor to condense?" and the following answer choices: 
- Dew
 - CO 2
 - CFCs
 - rain
 - SO2
 - H20
 - NaCl
 - h2o

Now knowing that water vapor cooling causes that water vapor to condense and water is made up of H2O molecules, choose the best answer.


 

        h2o 