Question

131.
The first vertebrates to appear on the earth were:
(1) Ostracoderm
(2) Osteichthyes
(3) Placoderms
(4) Condrichthyes​

Answer 1

Answer:

1. Ostracised

Actually the first vertebrate on earth is Mylinofulale.

But it isn't in your options.

From these four i think ostracoderm is the oldest.It originated about 251 to 552 million years ago.

Hope this will help you in further cofirmations

Answer 2

Option a, is the correct solution.

• Ostrachoderms were the first jawless fish to evolve during the Paleozoic era.

• These were the first vertebrates to appear on Earth.

• There are both extinct (e.g., Heterostracans) and living (e.g., Hagfishes and lampreys) members.

• A bony shield encased the head and thorax.

• Paired fins were a distinguishing feature.

• The caudal fin was discovered to be heterocercal.

• The ventral side housed the Mouth.

• There were numerous pharyngeal gill slits present.

• The nervous system typically contains ten pairs of cranial nerves.