An anthropologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, well-formed, and had four chambers, with no connection between the right and left sides. A reasonable conclusion supported by these observations is that the animal wasA) most closely related to mammals. B) most closely related to fish. C) most closely related to reptiles. D) most closely realted to athropods and molluscs. E) most closely related to amphibians.