Astronomer: Observations of the Shoemaker-Levi comet on its collision course with Jupiter showed that the comet broke into fragments before entering Jupiter's atmosphere in 1994, but they did not show how big those fragments were. Nevertheless, some indication of their size can be inferred from spectrographic analyses of Jupiter's outer atmosphere. After the fragments' entry, these analyses revealed unprecedented traces of sulfur. The fragments themselves almost certainly contained no sulfur, but astronomers believe that the cloud layer below Jupiter's outer atmosphere does contain sulfur. Since sulfur would have seeped into the outer atmosphere if comet fragments had penetrated this cloud layer, it is likely that some of the fragments were at least large enough to have passed through Jupiter's outer atmosphere without being burned up.
In the astronomer's argument, the two portions in boldface play which of the following roles?
Astronomer: Observations of the Shoemaker-Levi comet on its collision course withJupiter showed that the comet broke into fragments before entering Jupiter'satmosphere in 1994, but they did not show how big those fragments were.】 In hopes of gaining some indication of the fragments' size, astronomersstudied spectrographic analyses of Jupiter's outer atmosphere. These analyses revealed unprecedented tracesof sulfur after the fragments' entry. The fragments themselves almost certainlycontained no sulfur, but many astronomers believe that the cloud layer below Jupiter's outer atmospheredoes contain sulfur. Since sulfurwould have seeped into the outer atmosphere if comet fragments had penetratedthis cloud layer,it is likely that someof the fragments were at least large enough to have passed through Jupiter'souter atmosphere without being burned up. In the astronomer's argument, the twoportions in boldface play which of the following roles? A. The first is a claim that the astronomerseeks to show is true; the second acknowledges a consideration that weighsagainst the truth of that claim. B. The first is a claim that the astronomerseeks to show is true; the second provides evidence in support of the truth ofthat claim. C. The first and the second are each considerationsadvanced in support of the conclusion of the argument. D. The first provides evidence in support ofthe conclusion of the argument; the second is that conclusion. E. The first is a circumstance for which theastronomer seeks to provide an explanation; the second acknowledges aconsideration that weighs against the explanation provided by the astronomer