The geographic distribution of the Mesosaurus, a small swimming reptile that lived during the late Paleozoic, shows that the reptile lived on the southwest coast of what is now Africa and the southeast coast of what is now South America. This provides evidence that
a. the Earth was once much smaller in size.
b. the Atlantic Ocean was once much more shallow.
c. africa and South America were once joined into one continent.
d. migration between Africa and South America was once possible.
e. a land bridge once existed between Africa and South America.

C. Africa and South America were once joined into one continent.

Explanation:

Mesosaurus is an extinct genus of reptile, also called middle Lizard. It was significant in providing for the theory of continental drift (which explains that is the theory that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed ) because its remains were found southwest coast of Africa and south east coast of south America. This is because Mesosaurus is a coastal animal, and it seems very unlikely that the animals crossed the Atlantic ocean. Thus indicating the two continent might really have been joined together in the past.