OG详解-OG1 阅读 Q17

Choice A is incorrect because the text doesn’t describe any fluctuations in atmospheric carbon dioxide, so there’s no evidence in the text to support the conclusion that such fluctuations had different effects on different sauropod lineages. All that the text says about atmospheric carbon dioxide levels is that there weren’t increases at particular points that correspond with key moments in sauropod evolution. Choice C is incorrect because the text indicates that there weren’t significant increases in atmospheric carbon dioxide around the time of important periods in sauropods’ evolution toward larger body sizes, not that atmospheric carbon dioxide was higher when the largest sauropods lived than when sauropods first appeared. Choice D is incorrect because the text indicates that atmospheric carbon dioxide levels didn’t increase at important periods in sauropod evolution, not that higher levels would have affected that evolution. The text provides no information about how higher levels of atmospheric carbon dioxide might have affected sauropods.