PT44 LR2 Q17 Forum

[TheLuckyOne]

I despise these #17s. They ALWAYS suck

PLEASE, READ BEFORE RESPONDING.

Ok, maybe, it's my headache, but I have trouble with this stupid question. Here's why I don't like some of the choices.

The author suggests that there was something else in addition to cosmic dust to cause ice ages. Ok, by this logic D really adds nothing. Cool.
NOW, how does E add any new element besides just strengthening the idea cosmic dust and ice ages. (To tell the truth, D is even better than E since large bits cosmic rock are not necessarily cosmic dust, and these rocks raise additional dust from EARTH'S SURFACE (which is not cosmic)) And C's volcanic eruptions have nothing to do with the specific period we're dealing with.

In other words, if D is our bad answer adding nothing, how is C or E any better???? I merely fail to see it. Can someone enlighten me, please.

[autarkh]

C) strengthens by showing that atmospheric dust can affect climate; it makes the supposed causal mechanism more plausible.

E) strengthens by showing that the presence of rare (i.e. "cosmic") elements in sediment corresponds well to known ice ages, also making the causal connection more likely. In other words, this is evidence of the mechanism in action.

D) does nothing for the proposed CAUSAL mechanism (i.e. the cosmic dust itself causing solar dimming). The claim was not that cosmic debris would kick up terrestrial dust, which would, in turn, dim the Sun.

[TheLuckyOne]

SHIT! Why on earth was I strenghtening the wrong part of the argument. Such an easy question, and a mistake

Thanks.