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. 

[EX Q]: A tadpole is hatched. The tadpole eventually grows hind legs. The tadpole loses its tail. The tadpole becomes a frog. The frog mates with another frog to produce more offspring. A tadpole is hatched. The cycle begins again. 
[EX A]: Describe the life cycle of a frog

[EX Q]: Water comes into contact with something made of iron. The water combines with carbon dioxide in the air to form carbonic acid. As the acid is formed, the iron starts to dissolve. Some of the water breaks down into hydrogen and oxygen. The free oxygen and dissolved iron bond together. They form iron oxide, which is rust. 
[EX A]: How does rust form?

[EX Q]: Warm water rises off the seas. The water condenses as it cools and gets higher in the air. Then the condensation forms into clouds. The clouds travel over areas on land. The clouds reach a saturation point. The rain falls from the clouds. 
[EX A]:
How does rain occur?