The issue with answer choice (C) is that it states that the iridium being released caused the atmosphere to change the Earth's climate dramatically. But, we know from the passage that the Earth's climate changed gradually and we do not know necessarily whether the eventual change was a dramatic one or not, we merely know that this change caused many marine organisms to die out. "Fossil records indicate that for several hundred thousand years prior to the relatively sudden disappearance of the dinosaurs, the level of the sea gradually fell," (lines 50-53). The passage states that this gradual change "might well have been the result of a distortion in the Earth's surface that resulted from," the lava (lines 54-57). But again, we do not know whether the lava released enough iridium to have changed the Earth's climate dramatically.
On the other hand, answer choice (D) was definitely stated in the passage. Lines 39-40 explain just this: "Although Iridium is extremely rare on the Earth's surface, the lower regions of the Earth's mantle (which contains the lava) have roughly the same composition as meteorites and contain large amount of iridium."
So, as you can see, answer choice (D) was directly stated in the passage, whereas we have not been given sufficient evidence to infer answer choice (C).
Hope that clears things up! Please let us know if you have any other questions.
fableApril 21, 2020
I understand that D is stated in the passage but I do not understand how this is evidence for the lava eruption in India at the end of the crustaceous perditions. Lines 39-40 don't mention this and neither do the lines around it mention India.
