Harm to the respiratory and circulatory systems can come from \nOptions:\n- (A) Greenhouse gases\n- (B) hydrocarbons\n- (C) Sulfur dioxide\n- (D) nitrogen oxides\n- (E) burning coal\n- (F) fossil fuels\n- (G) emissions\n- (H) Greenhouse gasses
Hmmm, let me think. I don't want to be wrong, so I got to be careful.
User
Air pollution harms the respiratory and circulatory systems. Nitrogen oxides cause air pollution. Nitrogen oxides harms the respiratory and circulatory systems. The answer: (D).
Assistant