Which group comprises cartilaginous fishes like sharks and rays?

• A. Chitin
• B. Chordata
• C. Chondrichthyes
• D. Crustacea

Answer: (C)

Cartilaginous fishes have skeletons made of cartilage rather than bone, which defines this group. They are classified as Chondrichthyes, the class that includes sharks, rays, and skates. This group sits within the broader phylum Chordata, since they are vertebrates, but the label that specifically identifies sharks and their relatives is Chondrichthyes. The other terms refer to different things: chitin is a tough carbohydrate in many invertebrate exoskeletons; chordata is the phylum that encompasses all vertebrates; crustacea are crustaceans like crabs and lobsters, not fishes. So the group comprising cartilaginous fishes like sharks and rays is Chondrichthyes.