Q13 - The highest mountain ranges

[noah]

The discrepancy you need to resolve in this question is the following: If wind and rain relentlessly wear down mountains, why is it that the mountains are highest where these forces are most frequently found. We would expect that where those erosive forces are most common to be where the mountains are most worn down (and therefore not the highest). The information about the formation of the mountains is tangential to the main discrepancy.

What is particularly tricky about this question is that it's easy to lose sight of the discrepancy you need to try to resolve. As one later poster figured out, we're not trying to figure out why there isn't erosion up there. Nor are we trying to figure out why those mountains are so high. The issue is why are the erosive forces so prevalent at the top of mountains, a place they will inevitably wear down.

(A) resolves the discrepancy by explaining that it is the high elevation that creates the wind and rain, so that's why we find the wind and rain up there so often.

(B) is tricky. I first eliminated it because it seemed out of scope (vegetation?), but later I realized that the issue is more complex. (B) provides a reason that could explain why those mountains have not eroded (even though the wind and rain is up there), but doesn't explain why the wind and rain is so prevalent up there.

(C) is out of scope as we are concerned with the erosion of the mountains, not how they are built.

(D) is tempting, as it might seem to mitigate the discrepancy. But even if the high mountains sometimes have more and sometimes have less precipitation, we still don't know why we tend to find wind and rain on high mountain ranges, where we'd expect them to have worn down mountains.

(E) is out of scope -- it adds another fact that does not address the main discrepancy.

If one were to predict the answer, which is not really the best strategy, one might expect to see "While wind and rain are erosive, it takes eons longer to erode a mountain than the tectonic plates take to form one." Two problems with this: it doesn't address why we tend to see wind and rain up in the highest mountains, and we should focus on 1. identifying the discrepancy, and 2. eliminating wrong answers; we should not predict and look for our prediction.


#officialexplanation

[bradleygirard]

This is a very odd question to me, because it almost seems that depending on how you read it, you could easily come up with different answers. While (a) was tempting, I chose (d) because it seemed to be a very reasonable explanation of the apparent paradox. The highest mountain ranges are found in places where the erosive forces are at their highest. So to me the paradox, is why are these mountain ranges so high when they are constantly faced with these erosive forces? What seems like a perfectly reasonable answer is that these erosive forces may be a new phenomenon, simply that they haven't had time to work their magic. I didn't see the most important question being 'why do we find these extreme forces where there are high mountains?' any more than I saw it being 'why do we find high mountains where there are these extreme forces?'. Having looked over it now, I would say the best reason for eliminating (d) is that it has a subtle shift of scope, and while it may explain the rain, it doesn't mention the wind at all, which the stimulus mentions as one of the erosive forces. Tough one.

[noah]

Yes, (D) is tempting for the reason you mention, but it also is too weak in that the it states that the precipitation may vary. But, in the end, we're already told that the highest mountain ranges are where those forces are found, so even if (D) were to say "The amount of precipitation and wind that a certain region receives will vary considerably over the average age of a mountain's lifetime," this wouldn't undo the fact that the high mountains tend to receive the wind and rain -- we only know about unspecified "certain regions."

[LSAT-Chang]

Hi noah,
So our expected result is that we wouldnt find erosive forces to be prevalent in the highest mountain ranges since these forces wear the mountains down. So our unexpected result is that we see these forces to be prevalent in highest mountain ranges. But my question is how does A help explain the part about it still being possible that these erosive forces wear the mountains down? Since we need to reconcile the two, I dont see how A still allows us to hold "the erosive forces of wind and precipitation inexorably wear these mountains down" to be true. Does my question make sense?

[noah]

I see what you mean! Why are those mountains still there?

It doesn't resolve that issue, but it does resolve our surprise at finding the forces there. If the paradox were focused on "but those mountains are still standing" then (A) would be less ideal. And, on second thought, we already have a reason for the mountains still standing - those tectonic plates colliding.

I agree that it's a not rock solid answer , but alas, the LSAT has asked for the best answer, and the others have eroded due to the corrosive analytic power of your brain.

[dorbathedogslayer]

I think an unwarranted assumption is being made with (A). It says that wind and precipitation patterns may be more extreme where mountain ranges are higher, but does it necessarily follow that that would contribute to increased erosion?
If a concrete example is needed, I was thinking that drought, which would not contribute to increased erosion, but obviously qualifies as an extreme precipitation condition.

However, (B), which has been quickly dismissed, seems to unambiguously resolve why there might be more erosion at the highest mountain ranges. We know that vegetation reduces erosion, as we are told that. We also know it is not present in higher mountain ranges. Therefore, all other things being equal, which we have to assume I suppose, it follows that erosion will have to be higher where there is less vegetation -> in the higher mountain ranges. This also explains why the mountain ranges remain higher despite the higher erosion- because if they were lower, vegetation could perhaps grow on it, and hence the higher rates of erosion is reduced.

What do you think?

<EDIT - Ok I had another dozen looks at this question and I think what resolves it now for me is that the question is asking for things that would explain the increased "erosive forces" while the vegetation in (B) would have no effect on the forces, but rather mitigate the effects of those forces. So the lack of vegetation increases the erosion on the highest mountain range but does nothing to change the erosive forces themselves. (A) does offer an explanation though.


Dorba

[goriano]

I think an unwarranted assumption is being made with (A). It says that wind and precipitation patterns may be more extreme where mountain ranges are higher, but does it necessarily follow that that would contribute to increased erosion?
If a concrete example is needed, I was thinking that drought, which would not contribute to increased erosion, but obviously qualifies as an extreme precipitation condition.

However, (B), which has been quickly dismissed, seems to unambiguously resolve why there might be more erosion at the highest mountain ranges. We know that vegetation reduces erosion, as we are told that. We also know it is not present in higher mountain ranges. Therefore, all other things being equal, which we have to assume I suppose, it follows that erosion will have to be higher where there is less vegetation -> in the higher mountain ranges. This also explains why the mountain ranges remain higher despite the higher erosion- because if they were lower, vegetation could perhaps grow on it, and hence the higher rates of erosion is reduced.

What do you think?

Dorba

Could one of the LSAT experts explain why (B) isn't a viable answer? I agree with dorbathedogslayer's reasoning. It was deemed "out of scope" because it included vegetation, but I though resolve the paradox answer choices could do that, as with strengthen and weaken.

[noah]

Great work figuring that out dorba! It's really subtle stuff. One thing I noticed in your initial question is that you seemed to think that the answer should make something "necessarily follow." The answer for this question is the one that most helps to resolve the discrepancy - it doesn't have to make anything air tight.

Based on your post and the follow-up question by goriano, I have edited the original post. I hope that clears it up.

BTW, goriano, I prefer "LSAT geek" to "LSAT expert"!

I think an unwarranted assumption is being made with (A). It says that wind and precipitation patterns may be more extreme where mountain ranges are higher, but does it necessarily follow that that would contribute to increased erosion?
If a concrete example is needed, I was thinking that drought, which would not contribute to increased erosion, but obviously qualifies as an extreme precipitation condition.

However, (B), which has been quickly dismissed, seems to unambiguously resolve why there might be more erosion at the highest mountain ranges. We know that vegetation reduces erosion, as we are told that. We also know it is not present in higher mountain ranges. Therefore, all other things being equal, which we have to assume I suppose, it follows that erosion will have to be higher where there is less vegetation -> in the higher mountain ranges. This also explains why the mountain ranges remain higher despite the higher erosion- because if they were lower, vegetation could perhaps grow on it, and hence the higher rates of erosion is reduced.

What do you think?

Dorba

Could one of the LSAT experts explain why (B) isn't a viable answer? I agree with dorbathedogslayer's reasoning. It was deemed "out of scope" because it included vegetation, but I though resolve the paradox answer choices could do that, as with strengthen and weaken.

[boy5237]

Hey Noah,
I think this question is particularly tricky because, as you have said above, it's really easy to lose the sight in regards to what discrepancy we are trying to resolve.

I thought, initially, that the discrepancy was that "how do highest mountain ranges withstand the erosive forces?" (Erosive forces are prevalent there yet those ranges are still able to maintain their height)

If this were to be the "true" discrepancy, B would have been the right answer...

However, the actual discrepancy was, why those forces are prevalent... it wasn't even about mountain ranges.
Thus, A definitely solves this problem.

So my question is, for resolve problems, would you say paraphrasing a statement that starts with "although, however, yet, but, nonetheless," would actually represent the discrepancy of the argument? (assuming that those words are present... otherwise, I have to figure it out)

Thanks!

[tzyc]

Do we have to explain why wind and rain are so prevalent there for (B)? (The reason B is not correct as mentioned)
I think the problem is not explaining why it happens but rather why even it happens, there are still highest mountain. (so accept the 1st situation, need not to explain)
I think the 1st explanation actually makes more sense...vegetation is out of scope.
What did I miss here?

Thank you

[Dkrajewski30]

This is a very tricky question - probably the trickiest paradox question I've ever come across.

I chose B mainly because, like many others, I was looking to contribute to an explanation of a discrepancy that the question didn't want me to explain. As you're reading the stim, there is clearly a paradox going on. You're left wondering how the highest mountains could be found in places with a ton of erosive forces. After all, shouldn't the erosion wear these mountains down? And if that's the case, how can these mountains be the highest?

So B appears to at least be a partial explanation for how the highest mountains could be found in such places - there's simply less erosion at the top of the mountains. ...Or so it seemed..

After all, I don't even think B contributes to such an explanation, since if the highest mountains have less of something that mitigates the effects of erosion, then that further confuses the situation, as we have more reason to think the erosive forces should be wearing the mountains down to the point that they're not the highest mountains anymore. So for those of you suggesting that B would resolve the more obvious paradoxical situation in the stim, I don't believe it does, in which case that's one less answer to contend with even with a misunderstanding of what paradox the question's after.

In any event, this question was a clever trick from the test-writers. They probably knew that most people would be looking to resolve the wrong discrepancy. Because you're thinking about something being the highest and contrasting it with stuff that's supposed to wear it down, and that these two things supposedly coexist together? And yet all the question wants to know - merely - is how the two things could be correlated with each other. It's not asking you how the highest mountains remain the highest. It's not looking for some scientific explanation of how the highest mountains prevent the forces of erosion from wearing them down significantly. It's just wondering why we find the two together, and not how it is they actually coexist together. In essence, this question wants you to explain much less than you thought it did, which makes the right answer that much more difficult to find.

Personally, I got caught up with B and E. E seemed vaguely relevant because it addressed how the mountains form, and I figured a possible explanation of the *expected* paradox would be that this process somehow renders the wearing-down effects of erosion inconsequential, and that's how the highest mountains remain the highest. Even so, E's wrong on the grounds that if the thickened crust - which is what helps the mountain grow - is sinking, then in no way does that help explain how the mountains remain the highest. Nor it does it explain the targeted paradox, as E makes no mention of the erosive forces and why they exist among the highest mountain ranges.

If anything, given E, we ought to say that we expect the mountains to be shrinking and it would be a shock if they weren't, given that the thickened crust sinks over time in addition to the consideration that there are erosive forces at play.

Good question. This was a mind-boggler.

[beatthelsat]

After learning that I was focused on the wrong paradox, and seeing how A is correct, in hindsight it looks like the sentence stating, "The erosive forces of wind and precipitation inexorably wear these mountains down", is really a red-herring.

very tricky question.

[ShubhiT942]

B would be correct if the answer choice said that there was MORE erosion reducing vegetation because that would mean that this vegetation helped in preventing erosion and maintained the mountain ranges' heights. HOwever, because there is less erosion reducing vegetation, it would probably contribute to mountains eroding more; thus, not really help in explaining the discrepancy.

Answer choice A kind of alludes that the higher the mountain range is, the more erosive forces are prevalent but this is proportional to these high ranges are able to maintain their heights.

[AlbertY403]

Like others, I read the discrepancy as "How is it that the tallest mountain ranges are found in places where erosive forces are most prevalent." What or how can I train to not fall trap to false conclusions like that?

Thanks

[QingyiY938]

I was also stumped by this question on the first read. My immediate anticipation was that even though these erosive forces are with the highest mountains, maybe they weren't enough to actually decrease the height of these mountains. But I didn't find any of that and decided to move on.
When I came back to this question and after reading choice A, my mindset sort of switched and realized that A was the best answer out of all the other options.

I think the strategy to evaluating answer choices when you really don't see what you're looking for is to keep the conclusion and core of the question in mind. Here, our mission is to explain why these erosive forces occur at the same place as the tallest mountains. And A is the only one that directly address that question. It can be really easy to fall trap for wrong answer choices if you forget your mission.

So going through the other choices,

E. It's talking about the earth's crust and what not. So maybe over time these mountains reduce in height. But it tells me nothing about the erosion by wind and rain

D. OKay, now we're getting bit on topic. So D was probably my first pick on the first read but I asked myself does this explain why erosion is most prevalent where there are tall mountains? No, the key here is "most prevalent". we don't want to know why precipitation varies over time.

C. Completely irrelevant and it's the only answer choice I crossed out on first read. We don't care about how other mountains are formed

B. Honestly, I didn't understand B but I think what it's saying is that tall mountains have less vegetation that helps with erosion? If anything, it just tells us that they are likely to succumb to erosion. But again, I asked myself my mission question and it doesn't talk about the erosive forces

A. The elevation differences create these forces of erosion. I didn't choose A initially because I was looking for an answer that said these mountains were being eroded but still somehow the tallest. But the last sentence said "these mountains tend to be FOUND where erosive forces are most prevalent" it never said these mountains were subject to erosive forces. And also these mountains are so tall, they probably aren't eroded by rain. We know that there are places where the mountains are taller than the clouds.