Answer:
You either are referring to the fish Chordate, or the animal classification. In the case of the classification it is literally any animal that has developed any sort of dorsal fin, for example some snakes can fall under this classification.
The correct answer is C. lens. Lens is a convex sealed capsule containing a clear fluid and focuses light to the back of the eye. Iris is the colored part of the eye that contracts and expands under influence of ciliary muscle. Retina is the inner surface of back of eye. Cornea is a transparent and curved surface of eye that helps to focus light.
I’ll give you some key points and after that you should be fine, tide, swept underneath and over, density differences and climate change
You can prove they're related by their DNA