Given the task definition and input, reply with output. In this task, you are given a paragraph, and your task is to construct a question from the given passage. Construct question in such a way that (i) it is well explained in the paragraph, (ii) the words may/may not be present in the paragraph, (iii) it should start with what/how/describe. Avoid creating a question that (i) is just relevant to one or two sentences, and (ii) not relevant to passage. 

Warm air from the surface rises into the higher cold air. The water vapor in the air is condensed. The condensed water and dust forms a cloud. Wind in the cloud bounces the water droplets around. The bouncing droplets join together. The bigger droplets get heavy. The heavy droplets fall. As they fall, they join with more moisture in the air. The droplets get larger. Rain falls. 

How does rain form?