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variations in Vs variations among

by catseye » Tue Apr 26, 2011 9:39 am
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.
(A) changing the measured strain across a fault zone and varying
(B) changing measurements of the strain across a fault zone, and varying
(C) changing the strain as measured across a fault zone, and variations of
(D) changes in the measured strain across a fault zone, and variations in
(E) changes in measurements of the strain across a fault zone, and variations among

What is the difference between "variations in the electrical properties" and "variations among the electrical properties"

I can explain the wrong options as follows:

A. Changing and varying do not have subject.
B. changing does not have subject.
C. changing does not have subject.

In E, changes in measurements of the strain is not correct.

thanks.
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by atulmangal » Tue Apr 26, 2011 10:01 am
Hi, Nice question this is...it tested the concept of parallelism + redundancy
What is the difference between "variations in the electrical properties" and "variations among the electrical properties"


Among is used when more than 2 different items are present...so saying "variations among the electrical properties" is wrong.

For other options: see this concept

The requirement of can be || requiring of

But both of them can not be parallel to a gerund (requiring)

means, a proper noun (The requirement of) can be parallel to -ing plus of (requiring of) but they both can not be parallel to -ing only

In OP E, if u compare with Op D,

the measured strain ---> better
measurements of the strain---> redundant
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by e-GMAT » Wed Apr 27, 2011 6:09 am
Good job @atulmangal for explaining the question posted by catseye.
@catseye, I read through your choice analysis, and I feel that your reasoning is not exactly sound.

Consider the following sentence that has similar construction. Now see if your reasoning applies here on OG12#30 sentence as well:

For members of 17th century Ashanti nation in Africa, animal-hide shields with wooden frames were essential items of military equipment, protecting warriors against enemy arrows and spears.

Would you consider this incorrect because "protecting" does not have a subject?
See the spoiler below for explanation:
[spoiler]This verb-ing word is not acting as the verb of the sentence because it is not preceded by is/are/was/were/am.[/spoiler]

Well, you may find detailed approach to the question referenced in your original post below.

Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

Meaning Analysis
This sentence provides 4 warning signs for a major earthquake. These are:
1. Sudden fluctuations in local seismic activity
2. Titling and other deformations of crust
3. Changes in measured strain
4. Variation in electrical properties of rocks

A key thing to note in this sentence is that the intended meaning conveyed may be little difficult to comprehend because of the construction of elements 3 and 4. Elements 1 and 2 are clearly nouns (note that tilting is a noun here). Elements 3 and 4 are written in verb-ing form, making it appear as though these two are presenting results of the previous clause.

Warning signs may include A and B, changing the strain, and varying the electrical properties...

This cannot be the correct interpretation for the following reasons:
1. The meaning itself is non-sensical. It does not make sense to say that warning signs includes A and B, and this causes change in measured strain and variation in electrical properties.
2. Grammatically, this is incorrect. In the non-underlined portion of the sentence, "may include A and B" is written as "may include A, B" - If a list contains 2 elements, it should be connected properly using "and" in this case.

Error Analysis of Original Sentence
SV - This sentence contains 1 clause with SV pair = Geologists - believe
Verb Tense - Simple present tense is used
Pronoun - N/A
Modifiers - There are multiple modifiers in this sentence. We will focus on the modifiers in the underlined portion of the sentence only.
"¢ Modifiers for strain (element 3)
o Measured - adjective
o Across a fault zone - prepositional phrase
Parallelism - As discussed in detail above in meaning analysis, this sentence has serious parallelism issues.
This sentence provides 4 warning signs for a major earthquake. These are:
1. Sudden fluctuations in local seismic activity - NOUN
2. Titling and other deformations of crust - NOUN
3. Changing the measured strain - VERB-ING FORM
4. Varying the electrical properties of rocks - VERB-ING FORM
Clearly elements 3 & 4 in underlined portion are not parallel to elements 1 & 2. These can be made parallel by converting into noun forms as:
"Changes & variation"

Answer Choice Analysis
1. Choice A - Parallelism Error
2. Choice B - Parallelism Error
3. Choice C - Parallelism Error
4. Choice D - CORRECT
5. Choice E - Meaning
a. Meaning - The original sentence (Choice A) states - changes in measured strain - i.e. the actual strain has changed. This choice however states that measurements of strain changed - i.e. measurements change but we do not know if the actual strain changed or not. There is a very minute difference between these two but it is significant enough and we must keep a keen eye to detect these.
b. Meaning error from use of idiom - Both "variations in" & "variations among" are correct idiomatic constructions. But they convey different meanings. We need to select the appropriate construction to convey the intended meaning of the sentence.
i. "variations in electrical properties of rocks" implies that we are measuring the "electrical properties" and these are different from 1 rock to another.
ii. "variations among the electrical properties of rocks" means that we are talking about multiple electrical properties - say dielectric constant, conductivity, etc. - and there are variations among these. Clearly, this does not make sense here.

Thus, Choice D is correct.

For e-GMAT customers, this concept is covered at length in the Parallelism Concept Files
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by atulmangal » Wed Apr 27, 2011 7:02 am
@e-GMAT

Thanks for that wonderful and in depth analysis...can u please shed some light on the following concept of Modifiers

COMMA + Present Participial ---> Modify the whole preceding clause
Present Participial ONLY ------> Modify the preceding NOUN only

1st please clear m i correct about the above mentioned concepts and is there any exception in this rule???

Second, the past participial also act in this same way ???

I'm more interested to know about the rule in RED color...because for some questions OG explanations confused me a lot...

Thanks
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by e-GMAT » Wed Apr 27, 2011 8:27 am
Hi @atulmangal,

I am glad you liked the analysis of this question.
Now coming to modifiers: The rules that you have stated are correct with one minor correction.

1: COMMA + Present Participial ---> Modify the whole preceding clause
2: Present Participial ONLY ------> Modify the preceding NOUN or NOUN PHRASE only

2 also applies to past paricipial phrases as well. or verb-ed modifiers as I prefer to call it.

So really speaking these are the rules governing verb-ing & verb-ed modifiers:
Verb-ing modifiers
1: When separated by comma modifies the preceding clause
2: When not separated by comma modifiers the preceding noun or noun phrase

Verb-ed Modifiers
1: Always modify preceding noun or noun phrase.

We have covered this concept in detail in our concept titled "Modifiers - Verb-ing Modifiers". This concept is available in the free preview of the e-GMAT SC course. I suggest you review this concept in the free trial. You will be able to apply the concepts when you take the post assessment quiz in this file. After that definitely review a few OG sentence constructions to understand and apply these concepts on the Official Questions.

Here are a few examples from OG12 for verb-ed modifiers:
Verb-ed modifier modifying preceding noun = OG12#28
Verb-ed modifier modifying preceding noun phrase = OG12#26

There are no exceptions to this rule. However, I would like you to review the sentence construction of OG12#5 and see how this rule applies to that sentence. Let me know your thoughts and then we can carry this discussion further.

Also, I would be happy to clarify your doubts in OG questions.

Thanks,

Payal
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by atulmangal » Wed Apr 27, 2011 9:36 am
Hi Payal,

Thanks for the post...here is my doubt..

OG-12 D-49 question

As an actress and, more importantly, as a teacher of acting, Stella Adler was one of the most influential artists in the American theater, who trained several generations of actors including Marlon Brando and Robert de Niro.

A. Same as above
B. Stella Adler, one of the most influential artists in the American theater, trained several generations of actors who include
C. Stella Adler was one of the most influential artists in the American theater, training several generations of actors whose ranks included
D. one of the most influential artists in the American theater was Stella Adler, who trained several generations of actors including
E. one of the most influential artists in the American theater, Stella Adler, trained several generations of actors whose ranks included

For Op D, OG explain that "including" is referring to "generations of actors" NOT "Actors" that's why its incorrect....now as according the rule u mentioned
Present Participial ONLY ------> Modify the preceding NOUN or NOUN PHRASE only
This is Okay, but how we judge that -ing is actually referring to a NOUN or NOUN Phrase??? Is it like if a NOUN PHRASE is present then -ing will always refer to NOUN PHRASE only..????

One more question here:

for Op A, OG explain (apart from including), the placement of WHO is wrong as it is modifying Stella Adler so this pronoun should be placed near this...i believe that the the placement is wrong because WHO can refer to Stella Adler or to actors...so ambiguous..
what OG suggest is i believe a "preferable" construction not a "rule"...what do u think???

One more question, not related to this question, in general

we say use of COMMA + THAT is almost always wrong in GMAT as COMMA plus THAT introduces a NON_RESTRICTIVE clause, and for this purpose, COMMA + WHICH is preferred..??? I saw this rule applicable in many questions, is this correct??? can u please sate some examples and explain the difference (in terms of meaning). COMMA + THAT and only THAT is creating???

Thanks
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by e-GMAT » Thu Apr 28, 2011 8:16 pm
As I always say, treat rules as guidelines.

Grammar rules establish boundaries within which the authors use appropriate diction to express their thoughts...

So the rule under discussion is:
Noun modifiers (these include verb-ing modifiers (without comma), relative pronoun modifiers) modify closest noun or noun phrase.

Your question is - how to determine which one is being modified?
My answer - it depends on the context.

It may make sense for the modifier to only modify the closest noun.
It may make sense for the modifier to only modify the noun phrase.
It may make sense for the modifier to modify both - in this case - the modification is ambiguous and hence incorrect.

Lets see this in action. Note that I am using relative pronoun modifier to explain my point. Also, I quickly put together this set, so the sentence may be little weird :). But this does communicate the point.


Closest Noun
Ayurvedic medicine recommends application of eucalyptus oil, which is purified through several cycles.
It makes sense for the modifier to only modify the preceding noun. It does not make sense to say that application of oil is purified through several cycles.

Noun Phrase
Ayurvedic medicine recommends application of eucalyptus oil of clear color, which acts as a growth inhibitor.
It makes sense for the modifier to only modify the complete noun phrase. It does not make sense to say that color acts as a growth inhibitor.

Ambiguous
Ayurvedic medicine recommends application of eucalyptus oil with pungent smell, which acts as a growth inhibitor.
We do not know if the oil acts as growth inhibitor or smell acts as growth inhibitor.

Thus, as you can see, this is all context driven. How you should apply the rule is that such modifiers can modify nouns or noun phrases. Modifiers should be placed close to the entity they modify. These modifiers cannot modify the complete preceding clause. For the actual modification, use the meaning and context of the sentence to see what is actually being modified.

I hope this helps.

Thanks
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by catseye » Thu Apr 28, 2011 10:53 pm
Thanks to all for valuable discussion.
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by GMATMadeEasy » Fri Apr 29, 2011 10:37 am
@e-GMAT: that is excellent explanation. with all minute details. Thank you thank you !

Verb-ed Modifiers
1: Always modify preceding noun or noun phrase.

I thought past participle verb-ed modifier separated by comma modifies the preceding clause.

Example from OG12:

Diabetes, together with its serious complications,ranks as the nation's third leading cause of death,
surpassed only by heart disease and cancer.
(A) ranks as the nation's third leading cause of death, surpassed only
(B) rank as the nation's third leading cause of death, only surpassed
(C) has the rank of the nation's third leading cause of death, only surpassed
(D) are the nation's third leading causes of death,surpassed only
(E) have been ranked as the nation's third leading causes of death, only surpassed

OA is A ; surpassed only by .. modifies the whole clause and subject . Could you clarify please.
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by e-GMAT » Fri Apr 29, 2011 12:09 pm
I am glad you asked this question. Here is the explanation:
The RULE = Verb-ed modifiers modify nouns or noun phrases only.

But your doubt is very valid.

If we blindly apply the rule above without looking at the sentence structure, we cannot conclude that the verb-ed modifier in the sentence in question modifies "diabetes".

Here is the simplified sentence:

Diabetes ranks as third leading cause of death, surpassed only by xyz

Closest noun is death - so surpassed only by xyz modifes death - but this does not make sense as death is not surpassed by xyz.
Closest noun phrase is - cause of death, so it modifies cause of death. (Hold this thought)

Now pay attention to the verb in this sentence - ranks. This verb is linking verb. It is because the main verb in this sentence is a linking verb, that we can deduce that verb-ed modifier modifies diabetes. Here is how:

A linking verb B => A = B
So linking verb establishes an equation as shown above.

We know that if A = B & B = C, then A = C.

We know this modifier modifies the noun phrase - "cause of death".
Based on the linking verb rule, we know that diabetes = cause of death
Thus, verb-ed modifier modifies diabetes as well.

The other linking verbs are "is", "represents", etc.

I hope this is not overly complicated. Logically, I can easily infer that "surpassed only by..." modifies diabetes. Through the explanation above, I have made an attempt to explain why this is grammatically sound as well.
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by GMATMadeEasy » Fri Apr 29, 2011 12:42 pm
@e-GMAT: You made my day :) .
Now pay attention to the verb in this sentence - ranks. This verb is linking verb. It is because the main verb in this sentence is a linking verb, that we can deduce that verb-ed modifier modifies diabetes. Here is how:
A linking verb B => A = B
So linking verb establishes an equation as shown above.
This is not complicated, and I use the same logic in many questions and I can tell you this works.

So verb-ed modifier always modifies the preceding noun not a clause -- of course, i am thinking other than linking verbs cases :) ?

It is true though there is not a single OG question testing this.I did run a search sometime back.

However,there is a conflict of opinion as other experts have written verb-ed modifier does modify the preceding clause.

https://www.beatthegmat.com/og-12-modifi ... tml#333485
https://www.beatthegmat.com/sc-t80992-15.html#358518

Thanks a lot for all the above explanation.
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by atulmangal » Sat Apr 30, 2011 10:05 am
Hi Payal,

M sorry m replying late as i didn't get the email notification of this thread..Thank you so much for your posts...can u please clear one more doubt..

I read in many notes that use of COMMA + THAT is almost always wrong in GMAT as COMMA plus THAT introduces a NON_RESTRICTIVE clause, and for this purpose, COMMA + WHICH is preferred..??? I saw this rule applicable in many questions, is this correct??? can u please sate some examples and explain the difference (in terms of meaning). COMMA + THAT and only THAT is creating???

Thanks a lot
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by e-GMAT » Mon May 02, 2011 8:40 am
Hi Atul,

Grammatically comma+that is not correct usage. By definition 'that clause' presents required information and hence cannot be separated from the entity that it modifies by using a comma. When you do see comma before that, you will see a comma pair.

noun, noun modifier, that clause

In the above structure, comma is not separating that clause from its noun. The complete comma pair is used to separate out the noun modifier.

Mary lives on the street that is parallel to Baseline road.
Mary lives on the street, filled with citrus trees, that is parallel to Baseline road.
Here the comma pair separates "filled with citrus trees" from the rest of the sentence.

Here are two questions from GMATPREP (caution if you have not yet taken GMATPrep exams)

1: Ozone Question @ https://www.beatthegmat.com/prep-t2-q8-t5551.html
In this sentence, the non-underlined portion includes comma prior to that. But this comma does not separate out "that clause". This comma separates out the word "though" from the rest of the sentence.

2: Galileo Question @https://www.beatthegmat.com/gmat-prep-ga ... 34256.html
In this sentence, the correct choice includes comma prior to that. But this comma does not separate out "that clause". This comma separates out the phrase "in 1609" which modifies the action "hearing".

So do not blindly reject an answer choice that contains comma + that. Always understand the sentence structure and figure out the purpose of comma.

Hope this helps. :)
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by Whitney Garner » Mon May 02, 2011 10:03 am
catseye wrote:Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.
(A) changing the measured strain across a fault zone and varying
(B) changing measurements of the strain across a fault zone, and varying
(C) changing the strain as measured across a fault zone, and variations of
(D) changes in the measured strain across a fault zone, and variations in
(E) changes in measurements of the strain across a fault zone, and variations among
e-GMAT wrote: Parallelism - As discussed in detail above in meaning analysis, this sentence has serious parallelism issues.
This sentence provides 4 warning signs for a major earthquake. These are:
1. Sudden fluctuations in local seismic activity - NOUN
2. Titling and other deformations of crust - NOUN
3. Changing the measured strain - VERB-ING FORM
4. Varying the electrical properties of rocks - VERB-ING FORM
I definitely agree that this is a parallelism/list issue but I would just be a bit more specific and say that in 3 and 4, the words changing and varying are adverbial modifiers. This is certainly achieved by using a comma before an -ing participle. Calling them simply VERB-ING FORM might be potentially confusing - these ARE NOT verbs in their current usage.

Quick side-bar on participle -ing forms; they basically have 4 uses:

(1) Verb = when accompanied by a to be verb. (He was swimming when we arrived at his house)
(2) Noun = when standing alone (Swimming is my favorite activity on a hot day)
(3) Adjective = when attached to a noun (The swimming fish were extremely active, OR, The fish swimming in the pond were extremely active) Which fish? the swimming fish.
(4) Adverb = when used with a comma (We spent the entire day at the beach, swimming and building sand castles). What did we do at the beach? Oh, swam and built.

Notice that although we often think of -ing forms as verbs, they are more frequently used as other parts of speech (particularly on the GMAT)

In the original sentence, we therefore have what appears to be a list of 2 elements:
- fluctuations (n.)
- tilting & deformations (compound n.)

And then an adverbial modifying clause (note the comma before changing and varying) that would therefore have to modify the entire sentence; apparently the geologist's belief in these warning signs actually changes the measured strain and varies the electrical properties...This just doesn't make sense.

Other problem, if the list is only the first 2 elements, it would need to have an AND between the 2 elements to signal the end of the list. Because there is no AND in the non-underlined portion between the "fluctuations" and the "tilting and other def." we must assume that the list extends beyond these 2 elements. Therefore "changing" and "varying" need to be made nouns.

Eliminate A, B and C.

Between D and E, "changes in the measured strain" and "changes in measurements of the strain" mean 2 very different things. The first tells us the strain itself is changing (measured is just an adjective modifying strain), but the second says that the measurements are changing (measurements has become the new subject and strain is just a modifying prepositional phrase). To know which meaning is correct, we refer back to the original = "changing the measured strain" = measured is just the adjective and strain is the thing changing. Eliminate E, the answer is D.
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by e-GMAT » Mon May 02, 2011 1:14 pm
Whitney Garner wrote:Calling them simply VERB-ING FORM might be potentially confusing - these ARE NOT verbs in their current usage.
100% Agreed. :) That's exactly the point that I started my post with.
e-GMAT wrote:Would you consider this incorrect because "protecting" does not have a subject?
See the spoiler below for explanation:
This verb-ing word is not acting as the verb of the sentence because it is not preceded by is/are/was/were/am.
We offer a very comprehensive concept on verb-ing modifiers in our free trial. This concept covers all aspects of verb-ing modifiers. You can access the concept free of charge by registering at e-gmat
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