Instructions: 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: Water seeps into rocks. The water freezes and thaws. Cracks form in the rocks. Cracks also form when rocks heat up. The rocks slowly break down. 
Output:
What happens during weathering?