TASK DEFINITION: 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. 
PROBLEM: A fuel is heated in an oven. Above the oven is a tank of water that is sealed. The tank of water begins to boil above the oven. A the water boils steam is created. The steam is denser than air so it needs a place to go. The steam is forced out of the tank and into a piston. The piston moves up. The valve of the piston closes. The valve on the next piston opens. The steam fills the next piston, driving it up, and the other one down. 

SOLUTION: How does a steam engine work?

PROBLEM: Bacteria enters the body. Bloodstream. Cells in the body are attacked. Cells are killed. Different kinds of sickness are formed. 

SOLUTION: How does a virus cause disease?

PROBLEM: Minerals fill spaces between bits of sediment. The sediments become glued together. The glued together parts become hard like cement. The sediment becomes a big rock. The rocks erode slowly. The rocks come apart. The rocks become smaller rocks. The rocks continue to erode into smaller rocks. The process starts again. 

SOLUTION:
How does sediment turn into sedimentary rock?