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. 

Example input:  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. 
Example output:  What causes a volcano to erupt? 
Example 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.
Q: People separate different materials to be recycled. The recyclable materials go to a recycling center. The recycling center further separates the materials. Large equipment compacts the materials into bales. The recyclable materials are shipped to other recycling centers. The other recycling centers further process the materials that center specializes in. The materials are purchased by manufacturers. The manufacturers process the recycled materials the same way they would use new materials. The recycled materials are incorporated into new products. 
A:
How does recycling work?