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: Muscles work by expanding and contracting. A muscle fiber gets a signal from its nerve. Proteins and chemicals release energy to either contract the muscle or relax it. When the muscles contracts the bones connected to he muscle are pulled closer together. When the muscle relaxes the bones move farther apart. 

SOLUTION: How do muscles work?

PROBLEM: Magma rises through surrounding rock. Gas bubbles form and expand, causing lots of pressure. This pressure pushes the magma through weak spots in the earth's surface,. Magma flows out as lava. This can happen slowly or in a huge explosion. 

SOLUTION: What happens during a vocanic eruption?

PROBLEM: A plant dies. Bacteria from the ground migrate to the plant material. Bacteria release enzymes onto the plant material. The enzymes break down the plant cells to simpler components. The bacteria absorb the resulting components. 

SOLUTION:
How do bacteria break down dead plants?