All of these turtles have ... *
claws on their flippers and patters on their shell.
*Have 90% of the same DNA
These turtles also have a common ancestor similar to how humans and chimpanzees have a common ancestor the result in human and chimpanzee DNA being 97% the same.
Homologous: Animals having similar structures with different uses.
Vestigal structures Are structures that are not need by the animal anymore but have not evolved away yet.
The Green Sea Turtle has a tail but its tail is not need for swimming or really anything therefore its tale is a vestigal structure that has yet to evolve itself off.
Transitional Fossils are THe "in between structures", The structure that both the organism and its ancestor has that shows that they aren't all that different.