Respuesta :
B, a backbone.
Not A, because we know some species that aren't vertebrates and have a brain.
C. two germ layers, isn't a characteristic specific to vertebrates.
d. bilateral symmetry, no for the same reasons as A.
Not A, because we know some species that aren't vertebrates and have a brain.
C. two germ layers, isn't a characteristic specific to vertebrates.
d. bilateral symmetry, no for the same reasons as A.