You are presented with the question "What kind of vapor condenses to form fog in the air?" and the following answer choices: 
- h2o
 - Oxygen
 - H20
 - Dew
 - NaCl
 - sodium chloride
 - rain
 - mountain ranges

Now knowing that fog is formed by water vapor condensing in the air and components of water (H2O) 2, choose the best answer.


 

 h2o        