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: The outer ear collects sound waves. The sound waves travel from the outer ear to the middle ear. The eardrum changes the sound waves into vibrations. The hammer, anvil, and stirrup bones vibrate. The sound moves to the inner ear. The sound enters the liquid-filled cochlea. The cochlea vibrates. Small hairs in the cochlea move. Nerve signals are created. The brain understands the nerve signals as sound. 
Example Output: How does the human auditory system work?

Example Input: Fans blow air onto the evaporator's coils. The refrigerant within the coils absorbs the heat. The refrigerant changes from a liquid to a gas. The compressor compresses the gas, increasing the pressure. The hot, pressurized gas moves to the condenser. The gas condenses in the condenser and becomes a liquid again. Heat is radiated away from the condenser. The cooled liquid is returned to the evaporator. 
Example Output: How does an air conditioner work?

Example Input: Magma rises to the surface during a volcano. The magma undergoes changes in temperature. The magma undergoes changes in pressure. The magma cools. The magma solidifies. The magma crystallizes. Igneous rock is formed. 
Example Output:
How does igneous rock form?

