Clouds are formed by water vapor rising into colder regions of the atmosphere and condensing, and this water evaporates into water vapor and rises up into the atmosphere. Given these facts, what process must occur to form clouds among the following options:
- thunderstorms
 - Movement of an air mass
 - evaporation
 - nimbus
 - snow
 - water evaporating
 - chemical changes
 - cloudy and rainy weather


 

      water evaporating   