Which organism is a jawless fish?

Which organism is a jawless fish?

• A. Hagfish
• B. Shark
• C. Salmon
• D. Eel

Answer: (A)

Jawless fishes are the most primitive vertebrates and lack true jaws. Among the options, the hagfish fits this description: it has a cartilaginous skull and a persistent notochord but no hinged jaws, and it feeds by rasping with tooth-like structures on its tongue and by scavenging. In contrast, sharks have jaws made of cartilage, giving them biting capability, while salmon and eels are bony fishes with true jaws and mineralized skeletons. This combination of lacking jaws while the others possess them is why hagfish are the jawless fish.

Jawless fishes are the most primitive vertebrates and lack true jaws. Among the options, the hagfish fits this description: it has a cartilaginous skull and a persistent notochord but no hinged jaws, and it feeds by rasping with tooth-like structures on its tongue and by scavenging. In contrast, sharks have jaws made of cartilage, giving them biting capability, while salmon and eels are bony fishes with true jaws and mineralized skeletons. This combination of lacking jaws while the others possess them is why hagfish are the jawless fish.