Antartica-A good one...

[mchakrain]

Questions 16-17
On the basis of the available evidence, Antarctica has generally been thought to have been covered by ice for at least the past 14 million years. Recently, however, three-million-year-old fossils of a kind previously found only in ocean-floor sediments were discovered under the ice sheet covering central Antarctica. About three million years ago, therefore, the Antarctic ice sheet must temporarily have melted. After all, either severe climatic warming or volcanic activity in Antarctica’s mountains could have melted the ice sheet, thus raising sea levels and submerging the continent.

16. Which one of the following is the main conclusion of the argument?

(A) Antarctica is no longer generally thought to have been covered by ice for the past 14 million years.
(B) It is not the case that ancient fossils of the kind recently found in Antarctica are found only in ocean-floor sediments.
(C) The ice sheet covering Antarctica has not been continuously present throughout the past 14 million years.
(D) What caused Antarctica to be submerged under the sea was the melting of the ice sheet that had previously covered the continent.
(E) The ice sheet covering Antarctica was melted either as a result of volcanic activity in Antarctica’s mountains or as a result of severe climatic warming.

17. The reasoning in the argument is most vulnerable to which one of the following criticisms?

(A) That a given position is widely believed to be true is taken to show that the position in question must, in fact, be true.
(B) That either of two things could independently have produced a given effect is taken to show that those two things could not have operated in conjunction to produce that effect.
(C) Establishing that a certain event occurred is confused with having established the cause of that event.
(D) A claim that has a very general application is based entirely on evidence from a narrowly restricted range of cases.
(E) An inconsistency that, as presented, has more than one possible resolution is treated as though only one resolution is possible.

[sravna]

1. C
2. E because the author precludes other possibilities by saying "antarctic icesheeet must temporarily have melted".

[sravna]

D is very close. But the reason I didn't select D is (1) A vague terminology such as "a very general application" (2) D also says that the flaw is not basing the conclusion on more number of fossils. But the argument says that such a fossil has been previously found only in ocean-floor sediments and hence narrow range is not a problem. Even if more fossils are found like that it doesn't make a difference.

E is to the point saying precisely there is an inconsistency and the use of the word "must" in the conclusion suggests that the author is not considering other possibilities. The other possibility for example maybe that it may be the evidence of the first sort that has been found other than in ocean sediments as suggested in the phrase "previously found only in"

[mav]

1. should be C

2. between D and E, I think D is better

[sravna]

mchakrain,

Can you please post the OA ? I am curious.

[karmaholic]

1.C
2.E

Agree with sravna.

[mchakrain]

Oa :c & E