IMMA FISH!!!!!!!!

If I was originally a fish, how can I be so bad at swimming...?

How did fossils form?
Fossils usually form in sedimentary stone because the temperature and pressure are mild enough for fossils to preserve. Say if a fish died in water, it would fall to the river bed and decay. The bone will be covered by dirt and particles. After a period of time, the bones were fossilized and covered in deeper layers. Fossils are exposed because of wind, rain or earthquakes.

Homology

Homology means the resemblances between animals' body structures. If animals have similar body structures, they probably evolved from the same animal and are classified in the same group. For example, most land animals have the same "one, two and a bunch" arm structure, which was seen in Tiktaalik's fossil.