Blood Types. Distinct molecules called agglutinogens (a type of antigen) are attached to the surface of red blood cells. There are two different types of agglutinogens, type A and type B.
Fossil fuels are hydrocarbons, primarily coal, fuel oil or natural gas, formed from the remains of dead plants and animals. In common dialogue, the term fossil fuel also includes hydrocarbon-containing natural resources that are not derived from animal or plant sources.
Fossil fuels are basically any carbon based substance that is used by mankind as a source of energy. They are called fossil fuels because they usually are formed from the remains of dead animals and other organisms. The normal process that forms fossil fuels is pretty straight forward. An animal or plant dies and its remains are covered by sediment over time.