All turtles have common parts which classify all of them to be turtles. First of all, every turtle has a carapace, which is the top shell, and they have a plastron, which is the bottom shell. Scutes are scales that cover both shells, and they are made of keratin like fingernails. Like humans, turtles also have necks. They can fold their neck into their shells in an s-shape. The turtle's nostrils are near the top of the head so the turtle won't have to stick its head very far out of the water to breathe. A turtle has no teeth, but its beak makes up for it because it catches, holds, and slices food.