a) jawless fishes.
A: jawless fish
no..primitive is archaebacteria
It is as primitive as a cave man.
Bony Fishes
Reptiles
Mammals are most familiar vertebrates .
bony fishes
bony fishes
The rainbow XD lol
The group of vertebrates most closely related to birds are probably the dinosaurs.
Bacteria
Amongst the living the most primitive vertebrate is the Hagfish.