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: Tectonic plates smash together. The edges of the plates crumple up. The ridges are mountain ranges. Magma is forced to the surface. Magma forms a volcano. 

A: How are mountains formed?
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Q: 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. 

A: How do caverns form?
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Q: Warm, moist air moves from south to north. Cool, dry air moves from north to south. The air masses meet. The conditions that form are not stable because the air masses are so different. Winds are directed in a certain way because of how the masses interact. An updraft results. Winds start to form circular patterns in the updraft. A tornado can result. 

A:
How do tornadoes form?
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