TASK 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. 
PROBLEM: 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. 

SOLUTION: What causs a volcano to erupt?

PROBLEM: Chemical reactions in the battery causes a build up of electrons at the anode. This results in an electrical difference between the anode and the cathode. The electrons wants to rearrange themselves to get rid of this difference. The electrons go to the cathode. Electricty is created. 

SOLUTION: How does does a battery produce electricity?

PROBLEM: A stream or river must occur. Through erosion, the stream cuts into the soil and bedrock. Through continuous erosion, a deep gash is cut through. After many years the river may dry up. A dry ravine is left. 

SOLUTION:
How are ravines formed?