#27 - Concept Reference, Weaken

[Administrator]

Complete Question Explanation

The correct answer choice is (E).

Answer choice (A):

Answer choice (B):

Answer choice (C):

Answer choice (D):

Answer choice (E): This is the correct answer choice.

This explanation is still in progress. Please post any questions below!

[Katherinthesky]

Hello,

Can you please explain why (C) is incorrect?
I chose it because I read the first two types of sandstone as supporting the sandstorm theory since both types are created by wind.

I kept (E) as a contender but felt that (C) better weakened the sandslide theory.

Thank you in advance.

[bneufeld@alumni.iu.edu]

I think C is incorrect because the question is asking you to weaken the claim that the animals whose fossils were found AT UKHAA TOLGOD were killed by sandslides. Fossils in the second type of sandstone in areas other than the one the question is referring to doesn't necessarily weaken the claim. Just because the fossils in other parts of the desert were possibly caused by sandstorms doesn't mean that the fossils in this particular area were.

E is correct because it weakens the claim by introducing other possible causes for the sandstone forming in that particular way. If there could be other causes, it makes the sandslide hypothesis less convincing.

[Robert Carroll]

Katherinthesky,

The argument doesn't think it's impossible for fossils to be preserved in windblown sandstone. It thinks that the particular fossils in Ukhaa Tolgod were not preserved that way. And, in fact, in the second paragraph, all the fossils in Ukhaa Tolgod were found in the "third" type of sandstone, the type that isn't windblown. Answer choice (C) is saying that fossils in other regions of the Gobi Desert were found in the "second" type of sandstone, a type that is apparently blown by the wind. That wouldn't hurt the author's argument because the author is not committed to the idea that the second type of sandstone can't preserve fossils - it didn't preserve the fossils in Ukhaa Tolgod, of course, because no fossils were found in that type in that region. Other regions having their fossils preserved a different way would not be relevant to the argument.

bneufeld,

That looks correct to me. Good job!

Robert Carroll

[candleash]

Could you explain why D is wrong? I couldn't eliminate it properly. Is it because there is no reason to believe the words of geologists over the scientists in the passage?

[Adam Tyson]

The problem with answer D, candleash, is the timeframe. The fossils we are looking at in this passage are from 65+ million years ago, so it doesn't matter what may or may not have happened in the last 5 million years! Even if those geologists are correct, it has no impact!

[CristinaCP]

Could you please explain why A is incorrect? I eliminated it because in the 3rd paragraph, the passage states that it would have been possible for a sandslide to trap animals in its path. So A doesn't have much of an impact because even if scientists haven't directly observed it, we still know it's possible for the sandslide to have occurred/killed animals leading to the pristine fossils. Would you explain it differently?

[Luke Haqq]

Hi CristinaCP!

Your reasoning makes sense. This is a weaken question, and in the end, answer choice (A) doesn't have an impact. For that reason, it can be eliminated.

By contrast, answer choice (E) states that "There are several natural processes that can produce the third type of sandstone described in the second paragraph." This weakens the claim that it was particularly sandslides that produced this third type of sandstone that preserved the fossilized remains discussed in this passage. This answer choice raises the possibility that there could have been other causes.