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. 
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Question: 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. 

Answer: How do caves form?


Question: A man and woman mate. Embryo is C. Embryo grows and develops into a fetus inside the woman's womb. The fetus is born. Begins to grow and develop through infancy and childhood. In the teenage years the human experiences puberty. Reaches sexual maturity. At 18 the human becomes an adult. Adult may procreate continuing the cycle. 

Answer: Describe the life cycle of a human


Question: Plants start growing on or near the rocks. The roots of the growing plants start to break up the rock. The plant acids dissolve the rock. The rock is broken down into smaller pieces. Erosion begins. 

Answer:
How does weathering cause rocks to break apart?