The preserved remains of extinct animals, plants, or other species that perished millions of years ago are known as fossils. These fossils provide information on numerous extinct organisms as well as clues as to how evolution may have taken place. It is possible to infer an organism’s possible appearance and lifestyle from fossils. More crucially, we can compare current and fossilised organisms to learn how they relate to one another. For instance, the protein sequences of the T-rex dinosaur, which established its avian ancestry, have been recovered by scientists. This indicates that birds are the living descendants of (avian) dinosaurs. Additionally, the distribution of fossils provides information on the historical period during which different species first appeared.