Question

Earliest jawed vertebrates were

• A. Ostracoderms
• B. Placoderms
• C. Crossopterygians
• D. Elasmobranchs

Answer 1

The correct option is B Placoderms

Vertebrates are the subphylum of a Chordata. Placoderms were among the first jawed fish. The jaws are considered to evolve from the gill arches. Placoderms are the extinct class of armoured prehistoric fishes, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked.

So, the correct answer is option B.