OG4 阅读 Q49

Choice D is the best answer. In lines 71-75("But ... match"), the author explains how Lavigne's team proved that Quilotoa's eruption did not cause the Little Ice Age: "But when Lavigne's team examined shards of volcanic glass from this volcano, they found that they didn't match the chemical composition of the glass found in polar ice cores, whereas the Samalas glass is a much closer match." These findings show that Samalas, not Quilotoa, was responsible for the onset of the Little Ice Age.
Choices A, B, and C are incorrect because they focus on the difficulty of identifying the volcano responsible for the Little Ice Age, the magnitude of the volcanic eruption, and the researchers' experiment.