Preptest 52, Section 3, Questions 19 and 25 (LR) Forum

[HiLine]

Question 19: I can't justify answer choice A. How does the scenario undermine the theory?
Question 25: I am not convinced that A is a better choice than C. I must've missed something.

Any explanation would be appreciated.

BTW, is it just me or does Preptest 52 have more tough LR questions than most other preptests?

[Atlas LSAT Teacher]

For 19, if you argue that Tom is the killer and your theory receives the "strongest support" from the fact that he had a pair of white gloves, if it turns out that a lot of people in the area had those gloves, then poof, your evidence is not so strong. Similarly, if mammals, who were immune to the toxic plants, were found in that contorted position, then it's not the toxic plant that's causing the contortion.

Does that clear it up?

[Atlas LSAT Teacher]

25 is explained here, BTW

http://www.atlaslsat.com/forums/preptes ... r-f83.html

[UFmark]

Since I just took this PT last night and got both questions right, I'll attempt to explain my reasoning for selecting the correct answers.

For number 19, the theory pretty much says, angiosperm related death -> contorted fossils, and contorted fossils are used as the STRONGEST support for proving the theory(dinosaurs died because of angiosperm exposure). Answer "A" states that MANY fossils of large mammals are found in contorted positions. This effectively undermines the theory because in the stimulus we read that mammals were unaffected by angiosperms. So if they weren't affected by angiosperms, then why were so many mammals found in contorted positions? This would undermine the idea that angiosperm related death = contorted position since mammals were not affected by angiosperms.

Number 25 is relatively easy. Simply find the conclusion in the stimulus, "the more distant the period we are studying is, the less useful the study of the present becomes." So pretty much the more time from period being studied -> less useful PRESENT studies (a matter of TIME). Answer "A", which is the correct answer, breaks down to "Astronomers OFTEN draw INFERENCES about the EARLIER years from RECENT data." Then it follows by stating that "Unfortunately, they have been able to learn comparatively little about the ORIGIN of our solar system. So this conforms to the principle, EARLIER years = astronomers make inferences, however ORIGIN = very little useful data.

Answer "C" makes no reference to the principle illustrated in the passage. It makes no reference to a TIME disparity but to a gap in understanding.

Hopefully this has helped you. If you have any more questions feel free to ask as I typed this relatively quickly while eating my lunch.

[HiLine]

For question 19, even if fossils of large mammals are found in contorted positions, that does not reject the claim that the poison helps explain why dinosaur fossils are found in contorted positions. The poison could cause both. And even if the poison couldn't help explain it, why would that undermine the theory that the poison killed the dinosaurs?

I am sorry for going so much into details for this particular question; when I took the test I spent a lot of time on the question and still rejected all the answer choices... My problem is not as much about how to eliminate wrong answer choices as about how to recognize a correct one.

For question 25, I found the structure 'the more ... the more ...' in the stimulus, for the lack of which I rejected answer choice A. In addition, the stimulus reads '... to be rich in clues' yet '...less useful' whereas answer A reads 'infer comparatively little', which I think is in contrast with 'rich in clues'.
I agree that the time distance is not the exact equivalent of the world view distance mentioned in answer choice C though.

[UFmark]

For question 19, even if fossils of large mammals are found in contorted positions, that does not reject the claim that the poison helps explain why dinosaur fossils are found in contorted positions. The poison could cause both. And even if the poison couldn't help explain it, why would that undermine the theory that the poison killed the dinosaurs?

I am sorry for going so much into details for this particular question; when I took the test I spent a lot of time on the question and still rejected all the answer choices... My problem is not as much about how to eliminate wrong answer choices as about how to recognize a correct one.

For question 25, I found the structure 'the more ... the more ...' in the stimulus, for the lack of which I rejected answer choice A. In addition, the stimulus reads '... to be rich in clues' yet '...less useful' whereas answer A reads 'infer comparatively little', which I think is in contrast with 'rich in clues'.
I agree that the time distance is not the exact equivalent of the world view distance mentioned in answer choice C though.

You are taking for granted the fact that the theory draws its STRONGEST SUPPORT from the finding of dinosaur fossils found in contorted positions as a means for explaining an angiosperm related death. Do you not see how "A" would undermine this support?

Remember, the question stem is asking us to choose which answer would MOST undermine the theory. You seem to be treating the term "undermine" as "reject/disprove." Try to think of undermine as "weaken." The answer does not have to absolutely disprove or reject the theory, but merely weaken it.

It seems to me that you are too quick to categorize an answer as wrong. Try and use the contender/loser technique where you do not eliminate an answer unless you KNOW it is absolutely wrong and leave answers that may be applicable as contenders. After eliminating the absolute wrong answers you can go back and chose from the remaining "contenders."

[HiLine]

That makes sense. Starting from now I will slow down in eliminating answer choices like you suggested. Last question concerning the dinosaur question though, what is the role of the last sentence in the argument?

[zworykin]

The last sentence tells you, very importantly, that the theory receives its strongest support from the fact that many dinosaurs are found contorted. This is how you know that attacking the link between "contorted" and "angiosperms" is a very effective way to undermine the argument. Attacking the evidence that provides the theory's "strongest support" is a great way to weaken the argument, yeah?

[HiLine]

The last sentence tells you, very importantly, that the theory receives its strongest support from the fact that many dinosaurs are found contorted. This is how you know that attacking the link between "contorted" and "angiosperms" is a very effective way to undermine the argument. Attacking the evidence that provides the theory's "strongest support" is a great way to weaken the argument, yeah?

So is that an intermediate conclusion, a premise closely related with the previous premises or a standing alone premise?

[zworykin]

It's a premise. It's only marginally related to the previous premises, if at all.

[HiLine]

It's a premise. It's only marginally related to the previous premises, if at all.

I see. So the scenario in A undermines the theory since it suggests that a different phenomenon might have been the cause of the contorted positions of the dinosaur fossils, thereby undermining the theory's strongest support.

[mz253]

i have really simple answers to your questions:

19: A shows effect without cause.

25: the stimulus is talking about using "current" information to learn about "past" events. and the older is the past event, the less useful is the current information.

A: current information: recently collected data
past event: earlier years of our solar system
time wise: origin of the solar system (since the origin of the solar system is so long ago, so it's not useful ->"infer comparatively little about the origin"