A) The reverse is false.
A dog is a mammal which means that is a vertebrate animal, is warm-blooded, the mammal females have mammary glands, and newborns can be nourished with the milk that comes out of those glans, etc.
However, in this sentence, a reverse would be just wrong because a mammal is not the definition of a dog. The class Mammalia includes a variety of animal species that have some common characteristics, like the mentioned above, and many others that are distinctive in their species. Some other mammals include cats, whales, elephants, horses, giraffes, camels, cheetahs, and beavers.
