Fossils are the remains or impressions of dead bodies of ancient life, plants and animals which are preserved in sedimentary rocks.
There are some factors which play important role to be fossilized, they are:
- The organisms must contain hard parts inside them.
- After the death of organisms they must be covered by some protective layer which helps to preserve inside the earth.
A fossil can be any preserved remains, impressions or trace of any living beings from the geological age.Fossils are the primary source of information about history of life on earth. There are 3 main type of fossils, they are impression fossils, trace fossils and replacement fossils.