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.
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Question: Fuel is converted to energy when air and petrol mix. The car engine burns the mix of air and petrol. Hot gas from the burning pushes the pistons. The resulting energy powers the crankshaft. Crankshaft powers the gears. The gears make the wheels roll.

Answer: Describe how a car works

Question: Waste products are deposited in the blood. Blood is carried to the kidneys through the renal arteries. The kidneys contain filters inside. The filters capture the waste products. The waste is combined with water to make urine. The urine leaves the kidney and is collected in the bladder. The cleaned blood is returned to the body.

Answer: Describe how kidneys work

Question: Batteries are put in a flashlight. The flashlight is turned on. Two contact strips touch one another. A circuit is completed between the batteries and the lamp. The lamp in the flashlight begins to glow. The reflector in the flashlight directs the lamp's beam. A straight beam of light is generated. The flashlight is turned off. The circuit is broken. The beam is no longer visible.

Answer:
Describe how a flashlight works