PrepTest 111

Incorrect. The argument does raise the theory that Antarctica's ice temporarily melted 3m years ago, but it doesn't say that this theory has been "generally" accepted so this answer is incorrect.

Incorrect. First, the author never revisits this statement and says that it's not true. Second, the main point is about the ice covering, not the source of the fossils. Third, the final line says that the melting ice sheets could have raised sea levels, submerging the continent, thus suggesting the author does believe that the fossils could have come from ocean—floor sediment.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Main Point

Stimulus Summary:
Traditional theory — Antarctica has been covered in ice for 14m years
Phenomenon — 3m—year—old fossils from the sea floor were found under the ice there
New theory/explanation — About 3m years ago, the ice sheet melted temporarily (This could have happened via climate change or volcanoes, raising sea levels)

Answer Anticipation:
Whenever an argument sets out a theory—especially one that runs counter to an earlier theory—there's a really good chance that that's the main point of the argument. Here, the new theory—that the ice melted temporarily 3m years ago—includes a conclusion keyword ("therefore") and is supported by the argument bringing up how it could have happened. Let's find that new theory in the answers.

Answer Explanation:
The main point of the argument is that contrary to what is commonly believed (14m years of ice) the Antarctic ice sheet melted 3m years ago. Another way of saying that is that the ice sheet hasn't been present continuously for 14m years so this is the correct answer.

Key Takeaway:
New theories that run contrary to old ones are almost always the main point of an argument when one is present.

Incorrect. This answer is the premise supporting the main point—an explanation of how the fossils could have ended up under the ice sheet if it melted 3m years ago.

Incorrect. First, these two methods of the ice sheet melting are noted as two possibilities, not the only two possibilities. Second, this was supporting the idea that the ice sheet melted and submerged the continent—it's a premise, not a conclusion.