This category contains non-commercial scientific, educational, and governmental references to biomass and biofuel. Biomass is organic non-fossil material. It comprises the mass of all biological organisms, dead or alive, excluding biological mass that has been transformed by geological processes into substances such as coal or petroleum. Solid biomass comes in different forms including what comes directly from the “producers” (grass, trees, shrubs, crop husks, etc.) and that which comes as waste from the animals that consume the producers (droppings or dung from animals and waste from humans). Biofuel is any fuel that originates from biomass. The three classes of biomass used for combustion are solid (e.g. wood, dried plants and animal waste), liquid (e.g. ethanol, methanol and vegetable oil) and gaseous (e.g. bio-methane and hydrogen). Reference: Wikipedia: The Free Encyclopedia