Here is a question I am trying to find the answer to
Reptiles are a paraphyletic group because... ?
A) They include worm lizards, which have no limbs
B) The group doesn’t include birds
C) The group doesn’t include mammals
D) Not all of them have three- chambered hearts
I’m a bit confused about the reasoning. I know a paraphyletic group does not have all of its descendants so if birds were to be included it would become monophyletic. So is B the answer? Could anyone help explain it better?