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Register now and save up to $200 Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Free Veritas GMAT Class Experience Lesson 1 Live Free Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code ## To map Earth's interior, geologists use a network This topic has 5 expert replies and 8 member replies richachampion Legendary Member Joined 21 Jul 2015 Posted: 678 messages Followed by: 24 members Thanked: 31 times Test Date: ∞ → Target GMAT Score: 760 GMAT Score: 740 #### To map Earth's interior, geologists use a network Tue Jul 21, 2015 2:43 am Elapsed Time: 00:00 • Lap #[LAPCOUNT] ([LAPTIME]) To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior, most rapidly traveling through cold. dense regions and slower through hotter rocks. A. interior, most rapidly traveling through cold, dense regions and slower B. interior, which travel most rapidly through cold, dense regions, and more slowly C. interior, traveling most rapidly through cold, dense regions and more slowly D. interior and most rapidly travel through cold, dense regions, and slower E. interior and that travel most rapidly through cold, dense regions and slower OA: C Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums! ### GMAT/MBA Expert GMATGuruNY GMAT Instructor Joined 25 May 2010 Posted: 13368 messages Followed by: 1780 members Thanked: 12891 times GMAT Score: 790 Wed Jul 22, 2015 3:08 am richachampion wrote: To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior, most rapidly traveling through cold. dense regions and slower through hotter rocks. A. interior, most rapidly traveling through cold, dense regions and slower B. interior, which travel most rapidly through cold, dense regions, and more slowly C. interior, traveling most rapidly through cold, dense regions and more slowly D. interior and most rapidly travel through cold, dense regions, and slower E. interior and that travel most rapidly through cold, dense regions and slower A, D and E: cold, dense regions and slower Here, a reader might construe that slower is an ADJECTIVE intended to be parallel with cold and dense (both adjectives). The intended meaning is for slower to serve as an ADVERB modifying traveling. B and C convey this meaning more clearly by using the parallel forms most rapidly and more slowly: MOST RAPIDLY through cold, dense regions and MORE SLOWLY through hotter rocks. Eliminate A, D and E. The referent for which + PLURAL VERB must be the NEAREST PRECEDING PLURAL NOUN. B: waves that originate...which travel Here, which travel (which + PLURAL VERB) seems to refer to waves (the nearest preceding plural noun). As a result, that and which both have the same referent (waves). Two different pronouns cannot have the same referent. Eliminate B. The correct answer is C. _________________ Mitch Hunt GMAT Private Tutor GMATGuruNY@gmail.com If you find one of my posts helpful, please take a moment to click on the "Thank" icon. Available for tutoring in NYC and long-distance. For more information, please email me at GMATGuruNY@gmail.com. Thanked by: ngk4mba3236, Needgmat Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now. OptimusPrep Master | Next Rank: 500 Posts Joined 13 Mar 2015 Posted: 410 messages Followed by: 7 members Thanked: 120 times GMAT Score: 770 Thu Jul 23, 2015 7:54 pm A.interior, most rapidly traveling through cold, dense regions and slower "cold, dense" are modifying regions and slower is modifying travel. These adjectives cannot be a part of a list as they are modifying different things. B.interior, which travel most rapidly through cold, dense regions, and more slowly Here the referrent of the pronoun which is unclear. C.interior, traveling most rapidly through cold, dense regions and more slowly Correct D.interior and most rapidly travel through cold, dense regions, and slower "cold, dense" are modifying regions and slower is modifying travel. These adjectives cannot be a part of a list as they are modifying different things. E.interior and that travel most rapidly through cold, dense regions and slower "cold, dense" are modifying regions and slower is modifying travel. These adjectives cannot be a part of a list as they are modifying different things. _________________ Ankur 99th Percentile GMAT Tutor | Optimus Prep™ Optimus Prep™ GMAT Courses: www.Optimus-Prep.com/GMAT Free Online Trial Hour: http://www.optimus-prep.com/request-free-online-trial-hour/ Free GMAT Study Plan: http://www.optimus-prep.com/ebook/ Optimus Prep™ Rates: GMAT Private Tutoring Online:$80-100/hr.*
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Pal22 Newbie | Next Rank: 10 Posts
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Hi GMATGuruNY,

Please can you help elaborate on the rule - "Two different pronouns cannot have the same referent.". Are there other examples that you can also share please?

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Fri Oct 23, 2015 7:52 am
Pal22 wrote:
Hi GMATGuruNY,

Please can you help elaborate on the rule - "Two different pronouns cannot have the same referent.". Are there other examples that you can also share please?
B implies the following:
waves that originate in originate in the earth's crust
waves, which travel most rapidly through cold, dense regions

The pronouns in red both seem to refer to waves.
Two different pronouns -- in this case, that and which -- cannot have the same referent.

Other examples:
http://www.beatthegmat.com/gprep-sc-17-t277559.html
http://www.beatthegmat.com/the-scandinavian-assault-on-western-europe-culminated-in-the-t286698.html

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ngk4mba3236 Master | Next Rank: 500 Posts
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Tue Mar 29, 2016 3:40 am
GMATGuruNY wrote:
B implies the following:
waves that originate in originate in the earth's crust
waves, which travel most rapidly through cold, dense regions

The pronouns in red both seem to refer to waves.
Two different pronouns -- in this case, that and which -- cannot have the same referent.
have a quick question --

in GMAT, that and which clause can't be connected by conjunction and and hence can't be VALID parallel structure. am i correct ?

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Sat Apr 02, 2016 3:09 am
ngk4mba3236 wrote:
GMATGuruNY wrote:
B implies the following:
waves that originate in originate in the earth's crust
waves, which travel most rapidly through cold, dense regions

The pronouns in red both seem to refer to waves.
Two different pronouns -- in this case, that and which -- cannot have the same referent.
have a quick question --

in GMAT, that and which clause can't be connected by conjunction and and hence can't be VALID parallel structure. am i correct ?
This line of reasoning is valid.

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Tue Jun 28, 2016 10:43 am
Hi GMATGuruNY ,

I have a two questions:

1) Can you please explain that in OA HOW and WHAT COMMA+VERBing(TRAVELLING) refers to?

2) Can you please explain more about that and which clause can't be connected by conjunction and and hence can't be VALID parallel structure.

Please explain sir.

Thanks,

Kavin

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Wed Jun 29, 2016 5:32 am
Needgmat wrote:
Can you please explain that in OA HOW and WHAT COMMA+VERBing(TRAVELLING) refers to?
Generally, COMMA + VERBing serves to refer to the agent of the NEAREST PRECEDING ACTION.
OA: waves that...ricochet around its interior, traveling most rapidly through cold, dense regions.
Here, the action that most closely precedes COMMA + traveling is ricochet.
Thus, traveling serves to refers to waves, the agent of this action.
Conveyed meaning:
As waves RICOCHET, they are at the same time TRAVELING.

Quote:
2) Can you please explain more about that and which clause can't be connected by conjunction and and hence can't be VALID parallel structure.
Parallel forms must serve the SAME FUNCTION.
A that-modifier is an ESSENTIAL MODIFIER: one that is necessary to convey the intended meaning of the sentence.
A which-modifier is a NONESSENTIAL MODIFIER: one that can be removed without altering the basic meaning of the sentence.
Since a that-modifier and a which-modifier serve different functions, they cannot be connected by a conjunction such as and.

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Needgmat Master | Next Rank: 500 Posts
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Fri Jul 01, 2016 10:40 pm
Quote:
GMATGuruNY wrote:
Needgmat wrote:
Can you please explain that in OA HOW and WHAT COMMA+VERBing(TRAVELLING) refers to?
Generally, COMMA + VERBing serves to refer to the agent of the NEAREST PRECEDING ACTION.
OA: waves that...ricochet around its interior, traveling most rapidly through cold, dense regions.
Here, the action that most closely precedes COMMA + traveling is ricochet.
Thus, traveling serves to refers to waves, the agent of this action.
Conveyed meaning:
As waves RICOCHET, they are at the same time TRAVELING.

Quote:
2) Can you please explain more about that and which clause can't be connected by conjunction and and hence can't be VALID parallel structure.
Parallel forms must serve the SAME FUNCTION.
A that-modifier is an ESSENTIAL MODIFIER: one that is necessary to convey the intended meaning of the sentence.
A which-modifier is a NONESSENTIAL MODIFIER: one that can be removed without altering the basic meaning of the sentence.
Since a that-modifier and a which-modifier serve different functions, they cannot be connected by a conjunction such as and.
Hi GMATGuruNY ,

Thank you so much for your reply. All clear.

Thanks,

Kavin

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Sun Jul 03, 2016 6:02 pm
I am a little confused about choice C and choice E. I understand most rapidly and slower are not parallel in E. OG said "The action, ricochet, is further described in a participial phrase in which traveling...is then further described in a comparison of travel speeds in cold and hot regions of Earth's crust." I don't agree with it and I think two that-clauses in E are parallel and they all modify seismic waves. In choice C, the structure is "Clause + Comma + Travelling" and I think travelling ... modifies the subject of previous clause -- seismic waves. Am I correct or someone can correct me?
Thanks in advance!

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Mon Jul 04, 2016 5:22 am
Crystal W wrote:
I am a little confused about choice C and choice E. I understand most rapidly and slower are not parallel in E. OG said "The action, ricochet, is further described in a participial phrase in which traveling...is then further described in a comparison of travel speeds in cold and hot regions of Earth's crust." I don't agree with it and I think two that-clauses in E are parallel and they all modify seismic waves. In choice C, the structure is "Clause + Comma + Travelling" and I think travelling ... modifies the subject of previous clause -- seismic waves. Am I correct or someone can correct me?
Thanks in advance!
E: seismic waves that originate in the earth's crust and ricochet around its interior and that travel most rapidly through cold, dense regions
Here, the that-modifier in red serves to refer to seismic waves.
Its role is purely adjectival, describing the KIND of seismic waves under discussion.
What KIND of seismic waves?
Seismic waves THAT TRAVEL MOST RAPIDLY THROUGH COLD, DENSE REGIONS.

OA: seismic waves that originate in the earth's crust and ricochet around its interior, traveling most rapidly through cold, dense regions
Here, the COMMA + VERBing modifier in red serves to refer both to the preceding ACTION (ricochet) and to the agent of this action (seismic waves).
Unlike a that-modifier -- whose function is purely adjectival -- a COMMA + VERBing modifier plays both an adjectival and an ADVERBIAL role.
As an adjective, it describes the agent of the preceding action.
As an adverb, it serves to express an action happening AT THE SAME TIME AS or AS A DIRECT RESULT OF the preceding action.
In the OA, one function of COMMA + traveling is to serve as an ADJECTIVE describing the KIND of seismic waves under discussion.
What KIND of seismic waves?
Seismic waves TRAVELING MOST RAPIDLY THROUGH COLD, DENSE REGIONS.
However, COMMA + traveling is also an ADVERB modifying the preceding action -- ricochet -- since the act of TRAVELING happens as a direct result of this action.
For this reason, COMMA + traveling can be said to describe HOW seismic waves RICOCHET.

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If you find one of my posts helpful, please take a moment to click on the "Thank" icon.
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Thanked by: Crystal W
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Crystal W Master | Next Rank: 500 Posts
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Mon Jul 04, 2016 5:31 am
GMATGuruNY wrote:
Crystal W wrote:
I am a little confused about choice C and choice E. I understand most rapidly and slower are not parallel in E. OG said "The action, ricochet, is further described in a participial phrase in which traveling...is then further described in a comparison of travel speeds in cold and hot regions of Earth's crust." I don't agree with it and I think two that-clauses in E are parallel and they all modify seismic waves. In choice C, the structure is "Clause + Comma + Travelling" and I think travelling ... modifies the subject of previous clause -- seismic waves. Am I correct or someone can correct me?
Thanks in advance!
E: seismic waves that originate in the earth's crust and ricochet around its interior and that travel most rapidly through cold, dense regions
Here, the that-modifier in red serves to refer to seismic waves.
Its role is purely adjectival, describing the KIND of seismic waves under discussion.
What KIND of seismic waves?
Seismic waves THAT TRAVEL MOST RAPIDLY THROUGH COLD, DENSE REGIONS.

OA: seismic waves that originate in the earth's crust and ricochet around its interior, traveling most rapidly through cold, dense regions
Here, the COMMA + VERBing modifier in red serves to refer both to the preceding ACTION (ricochet) and to the agent of this action (seismic waves).
Unlike a that-modifier -- whose function is purely adjectival -- a COMMA + VERBing modifier plays both an adjectival and an ADVERBIAL role.
As an adjective, it describes the agent of the preceding action.
As an adverb, it serves to express an action happening AT THE SAME TIME AS or AS A DIRECT RESULT OF the preceding action.
In the OA, one function of COMMA + traveling is to serve as an ADJECTIVE describing the KIND of seismic waves under discussion.
What KIND of seismic waves?
Seismic waves TRAVELING MOST RAPIDLY THROUGH COLD, DENSE REGIONS.
However, COMMA + traveling is also an ADVERB modifying the preceding action -- ricochet -- since the act of TRAVELING happens as a direct result of this action.
For this reason, COMMA + traveling can be said to describe HOW seismic waves RICOCHET.
Thank you so much! Your explanation is crystal clear!

akara2500 Newbie | Next Rank: 10 Posts
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Sat Apr 22, 2017 7:36 am
GMATGuruNY wrote:
Needgmat wrote:
Can you please explain that in OA HOW and WHAT COMMA+VERBing(TRAVELLING) refers to?
Generally, COMMA + VERBing serves to refer to the agent of the NEAREST PRECEDING ACTION.
OA: waves that...ricochet around its interior, traveling most rapidly through cold, dense regions.
Here, the action that most closely precedes COMMA + traveling is ricochet.
Thus, traveling serves to refers to waves, the agent of this action.
Conveyed meaning:
As waves RICOCHET, they are at the same time TRAVELING.

Quote:
2) Can you please explain more about that and which clause can't be connected by conjunction and and hence can't be VALID parallel structure.
Parallel forms must serve the SAME FUNCTION.
A that-modifier is an ESSENTIAL MODIFIER: one that is necessary to convey the intended meaning of the sentence.
A which-modifier is a NONESSENTIAL MODIFIER: one that can be removed without altering the basic meaning of the sentence.
Since a that-modifier and a which-modifier serve different functions, they cannot be connected by a conjunction such as and.
Hi Mitch
Then how about Noun + Comma + Modifier + Comma + clause, this modifier between these 2 commas is also nonessential?

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