The correct answer is letter B. A notochord is what separates chordates from other species. It is described as a c<span>artilaginous skeletal rod that supports that body of chordate animals. This particular body part is very much visible in different kinds of fish.</span>
Fire algae are known as dinoflagellates because they have two flagella. A flagellum (pl. flagella) is a whip-like structure that allows a cell to move.
