HELPPP Which is NOT a characteristic of all vertebrates?
a well-developed brain protected by a skull
an exoskeleton
paired appendages
a backbone

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

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