A Researcher Who Is Interested in When Marsupial Traits Evolved

Multiple Choice

A researcher who is interested in when marsupial traits evolved does a comparative study of all the mammalian species of Australia.She finds that most Australian mammals are marsupials,and she concludes that marsupial traits originated in Australia shortly after Australian mammals were geographically isolated from the other continents.Is this conclusion valid?

A) Yes.
B) No,because she did not consider that the traits in question may be homologous.
C) No,because she did not study any non-Australian mammals.
D) No,because she did not consider the unique environmental problems that Australia posed for mammalian evolution.