In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant. 

Q: Waste builds up in the blood. Blood enters the kidney. Blood passes through nephrons in the kidney. Different kinds of waste are momentarily trapped in the kidney. Cleaned blood flows out of the kidney. Filtered waste accumulates in liquid form (urine). Urine flows out of the kidney into the bladder. 

A: waste ,blood ,cleaned blood ,filtered waste ,urine 
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Q: People breathe and expel carbon dioxide. Engines produce carbon dioxide. Living things produce waste. Waste decomposes. Decomposition produces methane. Water evaporates. Water vapor joins the atmosphere. Carbon dioxide, water vapor and methane are greenhouse gases. 

A: carbon dioxide ,methane ,water ,water vapor ,greenhouse gases 
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Q: Coal is mined out of the ground. Coal is pulverized into fine powder. The coal is mixed with hot air. The coal and hot air are blown into a boiler. The coal and hot air burn over a fire. Highly purified water is pumped through pipes in the boiler. The water turns into steam. The steam presses against turbines. The turbines spin. Electricity is produced. 

A:
coal ,hot air ,water ,steam ,electricity 
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