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. 

[Q]: 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. 
[A]: How does a steam engine work?


[Q]: There is a fetus in the womb. They are born and are a baby. The baby grows into a child. Puberty turns the child into an adolescent. The adolescent becomes an adult. An adult becomes an elderly person. The elderly person dies. 
[A]: Describe the life cycle of a human


[Q]: They take in fluids and liquids. They process the fluid. They take out the toxins. Produce urine. Urine is released. The nutrients are returned to the body. 
[A]:
Describe what kidneys do