题目选项分析

The impact of a large meteor nearly 65 million years ago can better account for the series of cataclysmic events attending the extinction of the dinosaurs than can the concomitant changes in the Earth's climate alone; the former best explains the sudden appearance of high concentrations of iridium, an element found in meteors and, in and of itself, in no way related to changes in the terrestrial climate.

The impact of a large meteor nearly 65 million years ago can better account for the series of cataclysmic events attending the extinction of the dinosaurs than can the concomitant changes in the Earth's climate alone—changes that can best be explained by the sudden appearance of high concentrations in iridium, an element that is found in meteors and, in and of itself, in no way related to changes in the terrestrial climate.