Imagine a scenario in which you, as a recently graduated zoology major, are accompanying an older high school teacher on a field trip. Students are trying to identify as many different classes of vertebrates as they can observe. At the end of the field trip, their list includes all of the traditional vertebrate classes. In addition to other vertebrates, the students observed snakes, lizards, and numerous bird species. Their list of classes included the classes Reptilia (for the snakes and lizards) and Aves (for the birds). To the surprise of the teacher, you tell the students that modern zoologists would suggest that their division of birds and reptiles into separate classes is probably not the best groupings for these animals. Which of the following statements reflect your explanation for your esponse?

a. Modern taxonomy has revealed that the subphylum Vertebrata (Craniata) is a polyphyletic group. Therefore, any attempt to identify classes within that subphylum is futile.
b. Modern taxonomy has bee influenced in recent years by cladistic analysis. Cladistic analysis insists that groups, like Reptilia, include all descendants of the group's common ancestor. That is not true for the traditional class Reptilia. Birds are also descendant from the common ancestor of snakes, lizards and other "reptiles."
c. Traditional taxonomic divisions were mostly guess work, based on little real data. They must totally abandoned
d. Traditional taxonomic methods relied on embryological evidence and the description of homologous structures. It also relied on the description of differences, such as endothermy in birds and ectothermy in reptiles to help define animal groups. New discoveries, including the use of molecular biological techniques and the discovery of new fossils, has revealed that some structures thought to be homologous are really analogous and apparent differences ar not real differences-for example we now know that some dinosaurs were endothermic