Q: Fact 1: An animal requires air for survival. Fact 2: Plants help make oxygen for the air. Given the two facts above, an animal requires what for survival?

OPT:
(I) a leash;
(II) rocks;
(III) chemicals;
(IV) stamina;
(V) plants;
(VI) proteins;
(VII) food;
(VIII) fossil fuel;
A:
(V)