What is the question to: "Cartridge-operated extinguishers contain the expellant gas in a separate cartridge that is punctured prior to discharge, exposing the propellant to the extinguishing agent."? The topic is Fire extinguisher.
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Answer: "how fire extinguisher works?"


What is the question to: "Currently the dominant technology for direct production is steam reforming from hydrocarbons ."? The topic is Hydrogen production.
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Answer: "how is hydrogen produced?"


What is the question to: "It is available as a commercial product in many countries, with similar variations in ingredients, cooking method, and other variables."? The topic is Potato bread.
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Answer:
"where to buy potato bread made without wheat?"