A person who specializes in the study of animals is called a zoologist. Zoologists who study certain kinds of animals have their own names.
The two words are Genus and Species.
B, Provide nutritional support to the embryo. It is not D, as the breasts are not part of the female reproductive system. It isn't C because during pregnancy, fetal and maternal blood do not mix. It also isn't D since women do not produce sperm.