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. 

Input: Consider Input: Rainwater picks up carbon dioxide from the air. Rainwater goes into soil. Water with carbon dioxide percolates through soil. The water becomes a weak acid. The water dissolves limestone. Caves form where the limestone was dissolved. 

Output: How do caves form?


Input: Consider Input: 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. 

Output: How are mountains formed?


Input: Consider Input: The gravity of the sun pulls its mass inward. There is a lot of pressure on the Sun. The pressure forces atoms of hydrogen to fuse together in nuclear reactions. The energy from the reactions gives off different kinds of light. The light travels to the Earth. 


Output: How is sunlight created?