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 Input:
Items are collected. The items are sorted. Trash is removed from everything else. Goes to a landfill. The items go into a baler machine for each kind of material. They come out as bales. The bales are shipped to manufacturers to use to make products. 

Ex Output:
How does recycling work?


Ex Input:
Waters flows downwards thanks to gravity. Enters the dam at high pressure. The moving water spins the turbines in the power plant. The turbines turn the generators. The generators spin, and produce electricity. The water leaves the dam at the bottom. 

Ex Output:
How is hydroelectric electricity generated?


Ex Input:
Some of the rock in the ground is made of limestone. Over long periods of time rain can hit the limestone. And cause a acidic reaction. The limestone will slowly disintegrate. A large gap with be where the limestone was. Result in the cave. 

Ex Output:

How do caverns form?