Possible answers: (A). skateboards; (B). Greenhouse gases; (C). Worldwide temperature increase; (D). major threat to health; (E). direct damage to the lungs; (F). running; (G). a lot of human deaths; (H). Temperature decrease;

Fact 1: Global warming is when worldwide temperature increases. Fact 2: Global warming is caused by carbon dioxide trapped in the atmosphere. Given the two facts above, what does carbon dioxide cause?
Answer:
(C).