In which situation would it be least likely for a scientist to revise her experimental methods?

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

b.have there own function.

thinking it would be d not too sure but i think it's right

my teacher would say no s