Geologists have found that streams in the Karoo basin of Sou

Don't you think

" ---- changed suddenly from the meandering shape typically found in well-vegitated zones to the braided pattern found in areas without deep-rooted vegetation to hold the soil together at the end of the Permian period 250 million years ago, "

would be better than the original? Is it OK to separate them that much?

Geologists have found that ... streams ... changed ... , from the meandering shape typically found in well-vegetated zones to the braided pattern found in areas without deep-rooted vegetation to hold the soil together.

(A) from the meandering shape typically found in well-vegetated zones to the braided pattern found in areas without deep-rooted vegetation to hold
(B) from the meandering shape typically found in well-vegetated zones to the braided pattern that they find in areas without deep-rooted vegetation for holding
(C) from the meandering shape typical in well-vegetated zones to the braided pattern found in areas where it is without deep-rooted vegetation for holding
(D) shifting from the meandering shape typically found in well-vegetated zones to the braided pattern found in areas where it is without deep-rooted vegetation for holding
(E) shifting from the meandering shape that is typical in well-vegetated zones to the braided pattern being found in areas without deep-rooted vegetation to hold

1)from X to Y -B -C -D -E
Easiest way to eliminate is to see that only A has correct parallel structure from A found in X to B found in Y

Others I am not so sure about:
2) typically found in > typical in
-- going by ear here... adverb "typically" correctly modifies verb "found" and sounds like what where are trying to convey that 'the plant is commonly found here'
"typical in" just sounds weird, 'typical of' sounds better

3) to hold > for holding
-- going by ear here too but infinitive sounds way better

Was thrown off on the commas here.

HI GMATNinja, EMPOWERgmatVerbal, generis, GMATRockstar, MentorTutoring

Can you help with options D & E. It is true that comma + shifting in Choice D and E is the comma + verb-ing modifier that modifies the preceding action.

In this case, the action that precedes comma + shifting is changed. And should make sense with Subject but here it doesn't make sense with subject.(Geologists)

Hello, NandishSS. Although it is true that the subject of the main clause is geologists, the subject of the embedded clause, the one that begins with that and acts as the direct object of the main clause, is streams. The -ing phrase connects logically to this subject:

streams in the Karoo basin of South Africa changed suddenly at the end of the Permian period 250 million years ago, shifting from the meandering shape...

I will admit that the question took me a minute and a half to work out, in part because I thought, based on your query, that (D) or (E) might be the answer and you simply did not understand the justification. There were other issues in each of those choices that prevented me from choosing them: it and being, respectively. I ultimately settled on (A) because I knew it was the one that I had the hardest time arguing against.

I hope that helps. Thank you for bringing the question to my attention.

- Andrew

MentorTutoring Thank you for your wonderful explanation

Idiomatically:
From X to Y

So it appears that only A holds this, while the other options fail to do so.
Also the meaning is clear in A.
Hope this helps

Geologists have found that streams in the Karoo basin of South Africa changed suddenly at the end of the Permian period 250 million years ago, from the meandering shape typically found in well-vegetated zones to the braided pattern found in areas without deep-rooted vegetation to hold the soil together.

(A) from the meandering shape typically found in well-vegetated zones to the braided pattern found in areas without deep-rooted vegetation to hold -- Correct

(B) from the meandering shape typically found in well-vegetated zones to the braided pattern that they find in areas without deep-rooted vegetation for holding -- should be 'to hold'; not clear what 'it' is referring to here.

(C) from the meandering shape typical in well-vegetated zones to the braided pattern found in areas where it is without deep-rooted vegetation for holding -- should be 'to hold'; not clear what 'it' is referring to here.

(D) shifting from the meandering shape typically found in well-vegetated zones to the braided pattern found in areas where it is without deep-rooted vegetation for holding -- should be 'to hold'; not clear what 'it' is referring to here.

(E) shifting from the meandering shape that is typical in well-vegetated zones to the braided pattern being found in areas without deep-rooted vegetation to hold -- 'that is' is unnecessary'

Can someone please explain the parallelism between X and Y here. I am not able to understand why are elements X (meandering..) and Y (braided pattern) not parallel in answer choices B, C, D and E. All of them are structurally nouns.


Is it the fact that (in choice B for example) when we add "that" after a noun (braided pattern), then we are comparing a noun entity (meandering shape typically found in well-vegetated zones) with a full clause (braided pattern that they find in areas without deep-rooted vegetation for holding)?

Similarly, in C, when we use "meandering shape typical in well vegetated zones" (noun) with "braided pattern found in areas where" (noun). I'm confused what's the issue with parallelism here. IF there is any. :-/

Please ignore the pronoun and other errors for now since I just want to understand the elimination on purely parallelism issue. Struggling with analysing the parallel entities in various idioms from a "structurally parallel" lens.

daagh IanStewart AndrewN mikemcgarry

You can't really use parallelism alone to get the right answer here. But I think you're only focusing on the start of each phrase ("meandering shape" and "braided pattern"), which are certainly parallel in isolation. But the units the sentence is comparing are not always parallel. We have one unit:

"the meandering shape typically found in well-vegetated zones"

For perfect parallelism, you'd want the second unit to have the same structure as the first:

"the braided pattern typically found in areas without vegetation"

say, is almost perfectly parallel. You don't often find this perfect parallelism in real GMAT questions, and it's not a grammatical requirement -- there are lots of minor deviations from strict parallelism that don't affect the clarity of a sentence. But if you changed the second unit to, say:

"the braided pattern areas without vegetation typically contain"

the comparison then becomes confusing (and "contain" is a strange word choice, but I won't concern myself with finding the perfect word just to illustrate the point), and you'd generally prefer clearer wording on a GMAT SC question. In this question though, you need to investigate the pronouns and the meaning of the second half of the sentence to decide among the answer choices; parallelism alone doesn't get you there.

GMATNinja VeritasKarishma EducationAisle MartyTargetTestPrep


What is the role of "to hold the soil together" in the sentence? What is it modifying?

Thanks in advance!

"to hold the soil together" gives the purpose of deep-rooted vegetation. It is an infinitive of purpose.

What about the modifier issue? "shifting......" should modify streams, which it does in(D) and (E), but in the modifier "from......" in (A), (B), and (C) is far apart from streams and seems like a run on run sentence or modifying something else.?.?.?

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