Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. Fossil fuels are fuels formed by natural processes such as decomposition of buried dead plants and animals.
Amongst the three major types of rock, fossils are most commonly found in sedimentary rock. Unlike most igneous and metamorphic rocks, sedimentary rocks form at temperatures and pressures that do not destroy fossil remnants. Sedimentary rocks are formed by the deposition of sediments layer by layer making it easy to contain fossils and fossil fuels. Sedimentary rocks are soft rocks, thus it dose not destroy the fossils and in a longer run we get the fossil fuels like coal and petroleum products, which are very important for human life.