Q:Answer the following question given this paragraph: Vertebrates evolved from primitive chordates. This occurred about 550 million years ago. The earliest vertebrates may have been jawless fish, like the hagfish in Figure below . Vertebrates evolved a backbone to replace the notochord after the embryo stage. They also evolved a cranium , or bony skull, to enclose and protect the brain. Q: Vertebrates evolved from primitive forms of which creature? Choices: - arthropods - humanoids - cephalopods - chordates A:
A:
chordates