Explanation:It is mainly composed of methane gas. (correct)Biogas is a mixture of inflammable gases (methane, sulphur dioxide, carbon dioxide, etc) produced by microbial activity that can be used as a fuelIt is a non-renewable source of energy. (incorrect)Biogas is a naturally occurring and renewable energy source that is produced by the breakdown of organic matter.It is preferred over other conventional energy fuels because it is a cleaner fuel, has no foul smell and can be used as a source of energy as it is inflammable.It is formed by the decomposition of cow dung in the absence of oxygen. (correct)It is formed by the decomposition of excreta (dung) of cattle in the absence of oxygen.It burns without smoke and leaves no residue. (correct)Biogas is an excellent fuel because it contains up to 75% methane. It produces no smoke and produces no residue, unlike wood, charcoal, and coal burning.Biogas is used as a fuel for cooking and lighting.