Usually, when organisms die, their bodies will decompose and be lost. But sometime some body parts may not decompose completely and they will eventually harden and retain the impression of the body parts. All such preserved traces of living organisms are called fossils. Fossils are the remains or traces of a plant or animal that existed in a past geological age, and that has been excavated from the soil. Fossilisation is the process in which an organism is converted into a fossil. Paleontology is the study of fossils.
There are two ways to determine the age of fossils. One way is to dig the earth and start finding fossils. The second way of dating fossils is by detecting the ratios of different isotopes of the same element in the fossil material.
