Aplatypus is classed as a mammal because it has fur and feeds its offspring milk, yet it lays eggs, which is uncommon for mammals but not for other vertebrates. which of the following pieces of evidence would be most in strengthening the case for continuing to classify it with the mammals? a. evidence that all vertebrates share a common ancestor. b. evidence that some platypuses have evolved to bear live young under certain circumstances c. fossil evidence of platypuses living alongside other ancient mammals d. dna evidence showing it was more closely related to mammals then other vertebrates