Possible answers:
(A). oil
(B). sugar
(C). coal
(D). Cars
(E). H2O
(F). CO 2
(G). He
(H). O2
Q: Fact 1: Carbon dioxide concentrations in the air have increased over the last decade dramatically. Fact 2: CO 2 is carbon dioxide. Given the two facts above, what has increased in the air dramatically over the last decade?
A:
(F).