Part 1. Definition
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. 
Part 2. Example
 Magma rises from deep in the earth. The magma goes into volcanos. The volcanos pressure the magma upwards. The pressure causes the magma to push through the surface of the volcano. The lava cools. The lava forms new rock. New magma is pressured to the surface of the volcano. The volcano bursts through the rock the formed after the last eruption. 
Answer:  What causes a volcano to erupt? 
Explanation: The process paragraph explains in steps about - the cause for volcano eruption. The keywords in the question are relevant to the process paragraph given. So, this is a good question.
Part 3. Exercise
Magma rises through cracks in the Earth's crust. The pressure causes plates to move. Magma explodes to the surface. The lava from the eruption cools to form new crust. After several eruptions, the rock builds up and a volcano forms. 
Answer:
What causs a volcano to erupt?