Some diseases are caused by mutations that are inherited from the parents and are present in an individual at birth, like sickle cell disease.
The global distribution of organisms and the unique features of island species reflect the evolution and geological change. Fossils. Fossils document the existence of now-extinct past species that are related to present-day species.
The first layer of the earth, the thinnest layer of earth
It can reproduce quickly. Single-celled organisms are smaller in size.