As the air at high altitude (in the Troposphere) moves away from the Tropics, the air cools and some water vapor condenses as clouds 
(the air at high altitude (in the Troposphere; moves; away from the Tropics) (the air cools and some water; vapor; condenses as clouds)
the air at high altitude (in the Troposphere the air cools and some water
moves vapor
away from the Tropics
condenses as clouds