Question

how did wegener explain the fact that mesosaurus fossils, an ancient freshwater reptile, showed up on different continents?
the fossils were moved by humans
the fossils must be of different species
the mesosaurus swam between the two continents
the continents were at one time joined together

Explanation:

Alfred Wegener proposed the theory of continental drift. He believed that the presence of Mesosaurus fossils on different continents was evidence that the continents were once joined together. Mesosaurus was a freshwater reptile and it would have been impossible for it to swim across wide ocean basins. So, the continents must have been connected in the past.

Answer:

The continents were at one time joined together.