Question

hagfish, lampreys, and sharks and rays have cartilaginous endoskeletons. did the first vertebrates have endoskeletons consisting of cartilage or bone?

Answer 1

Answer:

First, vertebrates have vertebrae. Vertebrae are made up of cartilage and bone. The vertebrae are shaped like a column. Second, vertebrates have a cranium. Cranium is a bony case. The cranium encloses a brain. Several lineages of vertebrates have other features. Other features include exoskeleton, jaws, endoskeleton, limbs, and amniotic eggs.