Question

Among vertebrates, the unique feature of lampreys and hagfish is the ________. among vertebrates, the unique feature of lampreys and hagfish is the ________. absence of jaws absence of a postanal tail absence of a backbone presence of a cartilaginous skeleton

Answer 1

The correct answer is absence of jaws.
Lampreys and hagfish are in the class Agnatha, they are jaw-less fish. The members of the agantha class are probably the earliest vertebrates. Scientists have found fossils of agnathan species from the late Cambrian period that occurred 500 million years ago.