It's a gas.
D000383:Agriculture / Q000379:methods; D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control*; D000818:Animals; D001709:Biotechnology / Q000379:methods; D002417:Cattle / Q000235:genetics / Q000378:metabolism*; D004063:Digestion / Q000502:physiology; D017752:Greenhouse Effect; D008697:Methane / Q000032:analysis / Q000378:metabolism*; D030781:Organisms, Genetically Modified / Q000378:metabolism
D008697:Methane