Answer: A
Explanation:
Gravity is when you drop something, but in this case you aren’t dropping the ball. It definitely isn’t chemistry because you aren’t changing molecules or anything so that only leaves A which is the most reasonable answer anyways.
Answer:
Kingdom, Phylum, and Class
https://www.portnet.org/cms/lib6/NY01001023/Centricity/Domain/252/classification%20packet%20key.pdf
Go there^
I hope that helps a bit :)