Answer:
d
Explanation:
because that's what I think it is
Mammals (Mammalia) are a class of vertebrate homeothermic amniotes (of "warm blood") that possess milk-producing mammary glands with which they feed the young. Most are viviparous (with the notable exception of the monotrematas: platypus and echidnas). A clear example of a mammal is man and his best friend, the dog.
This should not be included in the notes, because it is scientifically approved that mammals have the capacity to produce milk and give this food to their young, which is vital for humans or dogs as in the example
The answer is entomology (choice B). Root words tell you the simplest word to find the meaning of, affixes are the additions to the root word that have a few typical meanings that allow you to adjust your definition. Etymology is about the origin of words, whether it is related to a place, or a person, or in a foreign language. However, entomology is the study of insects and does not help one understand word meanings.
