Forward with biofuels.
D001674:Bioelectric Energy Sources / Q000639:trends*; D002482:Cellulose / Q000737:chemistry; D003246:Conservation of Energy Resources / Q000639:trends*; D018556:Crops, Agricultural / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry* / Q000302:isolation & purification*; D005060:Europe; D017752:Greenhouse Effect; D014481:United States; D003313:Zea mays / Q000737:chemistry
D000431:Ethanol; D002482:Cellulose