試題詳解

49. The oceans affect the biosphere by
I) producing a substantial amount of the biosphere's oxygen
II) adding carbon dioxide to the atmosphere
III) being the source of most of Earth's rainfall
IV) regulating the pH of freshwater biomes and terrestrial groundwater
(A) only I and III
(B) only II and IV
(C) only I, II, and IV
(D) only I, II, and III