Neuroscientists, having amassed a wealth of knowledge over the past

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that neuroscientists are now drawing solid conclusions about how the human brain grows and how babies acquire language, and over the past twenty years they have amassed a wealth of knowledge about the human brain and its development from birth to adulthood.

Concepts tested here: Meaning + Grammatical Construction

• The introduction of the present participle ("verb+ing"- “drawing” in this case) after comma generally leads to a cause-effect relationship.

A: Correct. This answer choice acts upon the subject - "Neuroscientists" - with the independent verb "are now drawing" to form a complete thought, leading to a complete sentence. Further, Option A uses the phrases "having amassed a wealth of knowledge over the past twenty years" and "are now drawing", conveying the intended meaning - that over the past twenty years, neuroscientists have amassed a wealth of knowledge about the development the human brain undergoes from birth to adulthood, and as a separate action, they are now drawing solid conclusions about how the human brain grows and how babies acquire language.

B: This answer choice fails to form a complete sentence; "having amassed" is part of a modifying phrase, and "are now drawing" is part of a dependent clause, meaning there is no independent verb to act upon the subject - "Neuroscientists". Further, Option B alters the meaning of the sentence through the phrase "development from birth to adulthood over the past twenty years"; the construction of this phrase incorrectly implies that over an unspecified amount of time neuroscientists have amassed a wealth of knowledge about the development the human brain underwent over the past twenty years, specifically, from birth to adulthood; the intended meaning is that over the past twenty years, neuroscientists have amassed a wealth of knowledge about the development the human brain undergoes from birth to adulthood.

C: This answer choice fails to form a complete sentence; "amassing" is a present participle acting as a noun modifier, and "are now drawing" is part of a dependent clause, meaning there is no independent verb to act upon the subject - "Neuroscientists". Further, Option C alters the meaning of the sentence through the phrase "development from birth to adulthood over the past twenty years"; the construction of this phrase incorrectly implies that over an unspecified amount of time neuroscientists have amassed a wealth of knowledge about the development the human brain underwent over the past twenty years, specifically, from birth to adulthood; the intended meaning is that over the past twenty years, neuroscientists have amassed a wealth of knowledge about the development the human brain undergoes from birth to adulthood.

D: The sentence formed by this answer choice alters the meaning of the sentence through the phrase "now drawing solid conclusions"; the use of the "comma + present participle ("verb+ing" - "drawing" in this sentence)" construction incorrectly implies that over the past twenty years, neuroscientists have amassed a wealth of knowledge about the human brain and its development from birth to adulthood, and as a result, they are now drawing solid conclusions about how the human brain grows and how babies acquire language; the intended meaning is that neuroscientists are now drawing solid conclusions about how the human brain grows and how babies acquire language, and, as a separate action, over the past twenty years they have amassed a wealth of knowledge about the human brain and its development from birth to adulthood; remember, the introduction of the present participle ("verb+ing"- “drawing” in this case) after comma generally leads to a cause-effect relationship.

E: The sentence formed by this answer choice alters the meaning of the sentence through the phrase "now drawing solid conclusions"; the use of the "comma + present participle ("verb+ing" - "drawing" in this sentence)" construction incorrectly implies that over the past twenty years, neuroscientists have amassed a wealth of knowledge about the human brain and its development from birth to adulthood, and as a result, they are now drawing solid conclusions about how the human brain grows and how babies acquire language; the intended meaning is that neuroscientists are now drawing solid conclusions about how the human brain grows and how babies acquire language, and, as a separate action, over the past twenty years they have amassed a wealth of knowledge about the human brain and its development from birth to adulthood; remember, the introduction of the present participle ("verb+ing"- “drawing” in this case) after comma generally leads to a cause-effect relationship.

Hence, A is the best answer choice.

To understand the concept of "Comma + Present Participle for Cause-Effect Relationship" on GMAT, you may want to watch the following video (~3 minutes):



All the best!
Experts' Global Team

Im no expert but this is what I think

B. The new placement of the prepositional phrase "over the past twenty years" changes the meaning of the sentence. Instead of modifying the verb amassed it now seems to modify adulthood.

C. The way this sentence is constructed suggest a compound predicate, but the first part of the sentence has no working verb. Amassing by itself does not function as the verb of the sentence - its a modifier. If you have mahattans sc they tell you that words connected by AND should be parallel.

D. Like B. D also has a shift in meaning. By getting rid of the word ARE the phrase "now drawing solid conclusions about the human brain grows and how babies acquire language." acts more like a modifier. Put this phrase in front and you'll see the change in meaning.

E. E has the same problem as D.

The correct answer A is grammatical - there isnt anything wrong with it.

Hi htskumar,

I'll leave the boys at egmat to explain their answer further for you, but see if I can help with your second question

OG12 says, The final descriptor in present tense, now drawing conclusions...does not fit the opening clause, which is in present perfect tense (have amassed a wealth...) ----> What does this exactly mean?

This means that 'have amassed a wealth' is an event that happened in the past in an action that is completed(past perfect tense if you will), but the 'now drawing conclusions' is happening now (present tense). In interpreting the meaning of the sentence, this does not make sense.

The correct answer (A) moves from 'having amassed' to 'now drawing' this is more correct, 'having done some thing I now do something else'

Does that help?

James

Neuroscientists,having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about the human brain grows and how babies acquire language.

A)Neuroscientists,having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are

B)Neuroscientists,having amassed a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years,and are
No verb for Neuroscientists
C)Neuroscientists amassing a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years,and are. No verb for Neuroscientists

D)Neuroscientists have amassed a wealth of knowledge over past twenty years about the brain and its development from birth to adulthood, "drawing " is modifying what "adulthood"

E) Neuroscientists have amassed, over the past twenty years, a wealth of knowledge about the brain and its development from birth to adulthood , "drawing " is modifying what "adulthood"



Note correct SV pair: Neuroscientists are

Hi Mugdha,

Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about how the human brain grows and how babies acquire language.

Once again, I would say that you have done a good job in analyzing this one. However, the clause split for this one is not accurate. Let's look at the clauses in this sentence:

Cl. 1: Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about
Cl. 2: how the human brain grows and
Cl. 3: how babies acquire language.

Since we cannot have a clause without an SV pair, the additional information cannot be identified as a clause because it does not have a Subject and a Verb.

I would never advise to skip the additional information completely while doing the PoE. The best way to answer questions where answer choices confuse us is to stay focused on the meaning of the sentence. You have understood the intended meaning of this sentence alright. Now let's compare that meaning with the meaning that we get from choices D and E.

Choice D: Neuroscientists have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, - Per this choice, now the focus (main point) of the sentence is that Neuroscientists have amassed a lot of knowledge... However, per the original sentence, the focus of the sentence is that Neuroscientists are now drawing conclusions... This choice shifts the focus of the sentence completely. The main point of the sentence in Choice A is now an additional information in this choice. On this basis, we can eliminate this answer choice.

Choice E: Neuroscientists have amassed, over the past twenty years, a wealth of knowledge about the brain and its development from birth to adulthood, - Incorrect for the same reason as explained above.

So keep the intended logical meaning of the sentence as the main guide while doing the PoE.

Hope this helps.
Thanks.
Shraddha

Hi Meghna,

Neuroscientists,having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about the human brain grows and how babies acquire language.

A)Neuroscientists,having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are

B)Neuroscientists,having amassed a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years,and are

C)Neuroscientists amassing a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years,and are

D)Neuroscientists have amassed a wealth of knowledge over past twenty years about the brain and its development from birth to adulthood,

E) Neuroscientists have amassed, over the past twenty years, a wealth of knowledge about the brain and its development from birth to adulthood ,

This sentence has three clause.
clause 1 : Neuroscientists,(subject)
having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood,(verb-ing modifier that modifies Neuroscientists)
are (verb) now drawing solid conclusions about
Clause 2 : how the human brain grows and
Clause 3 : how babies acquire language.(clause 2 and 3 are parallel)

there is nothing wrong with the above sentence. but we should reject all the other choices for good reasons.
Choice B) this choice is wrong because a comma +and is used before "are", implying that there is another verb before "are" in the sentence. however, there is no other verb in the sentence.
choice C) it has the same problem as choice B. In addition the placing of the modifier "over the past twenty years" changes the meaning. Now the reader conclude that the development of the brain was over past twenty years
choice D) I do not find any thing wrong with this choice. this choice says that Neuroscientists
have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, now drawing solid conclusions about how the human brain grows and how babies acquire language.
In this sentence the verb -ing form modifies entire preceding clause and expresses the result of Neuroscientists action which is having amassed a wealth of knowledge.
Choice E) Same analysis as for choice D.

what is wrong with my analysis for choices D and E?

Hi there,

Thanks for posting your query here, as suggested.

I'm happy you brought up this question, because it’s a very pertinent doubt and it shows that your thinking is thorough.

The problem with options D and E is in the use of present perfect tense. Note that the original sentence is in the present tense: Neuroscientists... are now drawing solid conclusions. In the original sentence, there is no verb in the present perfect tense. However, options D and E change ‘amassed’ into ‘have amassed’. ‘Have amassed’ is only referring to the period of twenty years, not to what is happening ‘now’. The present tense verb ‘are’ is necessary to make the meaning clear, but it’s missing from these two options. We’re talking about two separate actions here: what scientists have done over the past twenty years (amassed knowledge), and what they are doing now (drawing conclusions).

I hope this helps!

Regards,
Meghna

Hi e-GMAT experts,

In the question here, option A

The ing-modifier is supposed to modify subject-verb pair. So where is the verb here ?
Is "having" a noun modfier and not a ing modifier , Please clarify ?

Regards,

Hi ygdrasil24,

Note that, when placed adjacent to the subject of the clause, a "comma + verb-ing modifier" can modify either the subject or the entire clause. The modification is based on the context.

In this sentence the verb-ing modifier "having amassed..." is modifying the subject "Neuroscientists".

On a different note, the verb for the subject "neuroscientists" is "are drawing".

This question has already been addressed in detail in the following thread. neuroscientists-having-amassed-a-wealth-of-knowledge-over-96386.html#p1083520

Hope this helps

Regards,
Krishna

I am also your Verbal Live student.

in the above mentioned question OA is A. I did it right.

but I reasoned it on this line to eliminate D and E.

let suppose D is right for a Moment in that case Neuroscientists will have two subjects have and are so D and E cannot be correct. Is my line of thought correct?

Hi @honchos,

I'm assuming you meant that the subject 'neuroscientists' would have two verbs. However, 'are' is not present in options D and E, so the verb 'are drawing' becomes the modifier 'drawing' in these options.

Before we get to the problem in options D and E, let’s look at the intended meaning of choice A. Remember we need to first thoroughly understand the original sentence so that we can properly gauge the other answer choices.

Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about how the human brain grows and how babies acquire language.

This sentence indicates the following:
• Over the past 20 years, neuroscientists have collected a lot of knowledge about 2 things - brain and its development
• Neuroscientists are now drawing conclusions about 2 things - growth of human brain and acquiring language.
Key things to notice:

Two actions are being discussed:
a. In the past, scientists collected information
b. Now in the present context, scientists are drawing conclusions

Now let’s take a look at choice D:

Neuroscientists have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, now drawing solid conclusions about how the human brain grows and how babies acquire language.

Let’s focus on the sequencing of tenses in this sentence. For this, I will omit “now” for now. We will bring this back after this bit of discussion.

Neuroscientists have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, drawing solid conclusions about how the human brain grows and how babies acquire language.

Let’s read this sentence now and see what meaning it communicates.
• Over the past 20 years, neuroscientists have collected a lot of knowledge about 2 things.
• The verb-ing modifier can either present result of preceding clause or elaborate on the preceding clause. Let’s see which meaning is logical here:

o Elaborating - They collected a lot of knowledge in the past by drawing solid conclusions about 2 things.
 This seems illogical since one does not collect information by drawing conclusions.

o Result - They collected a lot of knowledge in the past and this led to them drawing solid conclusions.
 This seems rather logical. After they collected knowledge, they were able to draw solid conclusions.

But notice one very important thing. In this sentence, both the actions appear to have taken place in the past. The information was collected in the past and the conclusions were also drawn in the past.

Now bring back your understanding of choice A. Per choice A, collection took place in the past but the conclusions were being drawn in the present.

So this is the first reason for rejecting choice D - the shift in the meaning of the sentence.

Now let’s bring back the word “now”. This word interferes with the logical sequence of actions established in choice D. The logical sequence as we determined was that both actions took place in the past, but the presence of “now” forces the second action to take place in present, thereby creating a conflict.

And lastly, there is a focus shift in choice D.

Note that modifiers typically do not present the main point of the sentence: they only give additional information. In the original sentence, the subject of the main clause is “Neuroscientists” and the verb is “are drawing”. So, the intended focus is to say that neuroscientists are now drawing solid conclusions about something. This focus is now shifted to the collection of information.

So, in conclusion:

It’s very important to understand the meaning of the original sentence so that you can assess answer choices in the appropriate light. Remember, grammar is a tool to help you communicate ideas. But there is no use of learning about grammar rules if you do not pay attention to what it is that you have to communicate using these tools.

I hope this helps!

Regards,
Meghna

Although it is already explained, I am not clear with it. And I also posted the same query before.

OE for Option (D).

The final descriptor in present tense, now
drawing conclusions ... does not fit the
opening clause, which is in present-perfect
tense {have amassed a wealth ...) and seems
to modify adulthood.

Scientists have amassed a wealth of knowledge, now drawing solid conclusions.......

What is the problem with having Present perfect as main clause and a descriptor in present tense?

Second,

As in GMAT lingo, we know that -ING modifier is used for two things (1). Additional info about preceding clause (2). Result of preceding clause.

Then why OE /OG rejects option (D) saying that final descriptor seems to modify ADULTHOOD

PPS: I have read the above explanation by MEGHNA, but still there is doubt.

Hi Saurabh,
Thank you for posting your query here.


There are two problems with option D, as Meghna explained above:

1. Shift in Focus: In the original sentence the information that neuroscientists have amassed a wealth of knowledge is given in the form of a modifier. Also, it seems that the main point that the sentence wants to convey is what scientists are doing now after they have already amassed a wealth of knowledge. Now, option D shifts the focus of the sentence to the modifier part. So, this is an error.

2. Also, per the original sentence the neuroscientists have completed the action of amassing the wealth over a duration of 20 years. The verb-ing modifier "drawing" presents the result of this clause that the action of amassing the wealth of knowledge has resulted in drawing some conclusions. As we know, the verb-ing modifier takes the tense of the preceding clause in such cases. So, per this choice the conclusions are being drawn for the last 20 years. However, the presence of the word "now" interferes with the logical sequence of the actions because it indicates that the action of drawing conclusions is taking place in the present. So, there is a conflict in the meaning.


Now, the explanation provided by the OG in this case states something else. Here, the verb-ing modifier "drawing" modifies the preceding clause, not the preceding noun "adulthood".



Hope this helps!
Regards,
Deepak

egmat,

A question, in the course you say that , -ing mod modifies the preceding CLAUSE. However "Neuroscientists" is not a clause, its a Subject\noun, so is the ,-ing construction correct?.. I eliminated A because of it. I thought that construction without comma would be the correct one since if there is no comma, then -ing modifies the preceding noun.

Thank you!

Present participle modifiers (-ing modifiers) can work the same way any other modifier does: modifying the noun touching the modifier. In addition, these modifiers may also be used to modify either the preceding clause or the subject of the preceding clause.

Well, since this is an official question, it is obviously correct.


Yes, but that is only true if there is a clause before the present participial phrase.

Thank you for the replies.

Does it mean that the comma after Neuroscientists is optional?