A fossil is the traces or remains of a once-living animal or plant that was conserved in rock or other substantial before the foundation of verified history. The term also is used to define the fossil fuels (coal, oil, natural gas and petroleum) that have been shaped from the leftovers of antique animals and plants. It is rare for whole creatures to be conserved. Fossils typically signify the hard portions, such as shells or bones of animals and greeneries, woody or seeds parts of plants. Fossils happen on each landform and on the ocean floor.