First off, you must understand what proper nouns are. Unlike nouns, proper nouns name a specific person, place or thing. While nouns simply name a person place or thing. A few examples of nouns would be girl, boy, dog, town and so on. And a few examples of proper nouns would be Abby, Sam, Golden Retriever, Springfield and so on. And in this situation, the proper nouns would be African and Pennsylvania. The reason why these two words are proper nouns is because these words name a specific type of people, which is Africans, and a specific type of place, which is Pennsylvania. Anyways, I really hope this helps!
