Fossil is a trace of an animal or plant of a past geologic age that has been preserved in Earth's crust. Fossils can be broadly divided into body fossils and trace fossils.
Body fossil – The remains of the part (or all) of an actual organism. Example: Dinosaur bone.
Trace fossil – Trace fossils are traces or marks left behind by an organism. They show an organism was there, but are not the actual organism itself (which would be a body fossil). Dinosaur footprints and worm burrows are examples of trace fossils