Q: Fact 1: Burning fossil fuels increases the carbon in the atmosphere. Fact 2: Increased atmospheric carbon dioxide increases greenhouse effect and warms the earth. Given the two facts above, what can warm the earth?

Pick from: (I) evaporation; (II) burning fossil fuels; (III) our nearest star; (IV) rain; (V) electromagnetic energy; (VI) nuclear fusion; (VII) heat energy; (VIII) magma;
The answer is:
(II)