Plants and animals require special conditions in order to be transformed into fossils after they die.

Therefore, the chance of one becoming a fossil is very small, and the chance of that fossil being discovered by a human being is even smaller.

For an animal or plant to turn into a fossil, it must be buried. If a plant is exposed to the air, it will eventually rot. The bodies of exposed animals will be eaten by scavengers. Sun and rain will eventually cause bones to disintegrate.

On the other hand, if the remains are buried, they will be preserved. Chemicals will enter the animal or plant, causing it to harden. These are the same chemicals that transform sand into rock. When the body of an animal or plant is hardened in this way, it is said to have been fossilized.

Many bones are preserved in river and lake sediments. Fossils are also easily formed in caves, where the remains of living creatures become buried by debris that is washed into the caves

Usually, only the hardest parts of an animal or plant, such as the bones of an animal, are fossilized.

Once in a while, the soft body parts are fossilized, but this will only happen if they are buried very quickly. This is most likely to occur when a volcano erupts.