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. in hopes of gaining some indication of the fragments’ size, astronomers studied spectrographic analyses of jupiter’s outer atmosphere. these analyses revealed unprecedented traces of sulfur after the fragments’ entry. the fragments themselves almost certainly contained no sulfur, but many 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?
(a)the first is a claim that the astronomer seeks to show is true; the second acknowledges a consideration that weighs against the truth of that claim.(b)the first is a claim that the astronomer seeks to show is true; the second provides evidence in support of the truth of that claim.(c)the first and the second are each considerations advanced in support of the conclusion of the argument.(d)the first provides evidence in support of the conclusion of the argument; the second is that conclusion.(e)the first is a circumstance for which the astronomer seeks to provide an explanation; the second acknowledges a consideration that weighs against the explanation provided by the astronomer.