Which of these would a paleontologist be most likely to do in order to determine whether a fossil represents a reptile or a mammal? A) Look for the presence of milk-producing glands. B) Look for the mammalian characteristics of a four-chambered heart and a diaphragm. C) Because mammals are eutherians, look for evidence of a placenta. D) Use molecular analysis to look for the protein keratin. E) Examine the teeth.