GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 14 Nov 2018, 16:33

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

## Events & Promotions

###### Events & Promotions in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
• ### \$450 Tuition Credit & Official CAT Packs FREE

November 15, 2018

November 15, 2018

10:00 PM MST

11:00 PM MST

EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth \$100 with the 3 Month Pack (\$299)
• ### Free GMAT Strategy Webinar

November 17, 2018

November 17, 2018

07:00 AM PST

09:00 AM PST

Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# Some anthropologists believe that the genetic homogeneity

Author Message
TAGS:

### Hide Tags

Retired Moderator
Joined: 14 Dec 2013
Posts: 2990
Location: Germany
Schools: HHL Leipzig
GMAT 1: 780 Q50 V47
WE: Corporate Finance (Pharmaceuticals and Biotech)
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

21 Jun 2016, 12:21
2
debbiem wrote:
daagh wrote:
A at some time in the past our ancestors suffered an event, greatly reducing their numbers ------ A hyphen is not the tool to connect two ICs.
B that at some time in the past our ancestors suffered an event that greatly reduced their numbers -------- ‘that ’ is the right connector ---correct choice.
C that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced ------- altered notion; it looks as if the ancestors suffered a calamity in order to reduce their numbers.
D some time in the past our ancestors suffered an event from which their numbers were greatly reduced -------- conjugation of two ICs with hyphenation is wrong.
E some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly, ------ same as in D

Dear Sir,

Is the main reason of choosing b/w B and D is that D has hypen in between and not a semi colon..?
Had there been a semicolon would both B and D be equally correct..?

A hyphen (dash) can be used in place of semicolon - hyphen is a versatile punctuation and can replace comma, semicolon or colon. Hence punctuation is NOT the reason that D is wrong. Following is a reason why A, D, and E (choices without "that") are wrong:

some-anthropologists-believe-that-the-genetic-homogeneity-134793-20.html#p1681019

Moreover "event from which" is not correct usage.
Manager
Joined: 30 Mar 2016
Posts: 51
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

Updated on: 07 Jul 2016, 03:40
ChrisLele

I have a doubt regarding your explanation of answer 'A'. According to my understanding, Greatly reducing is a -ing modifier preceded by comma which generally modifies the entire clause or is used to indicate the result of preceding statement. So in this case the modifier modifies the entire clause that at some time ancestors suffered an event and this led to great reduction in their number. So, according to me the modifier usage is correct. Can you please point out the flaw in my understanding?

ChrisLele wrote:
In answer choice (A) there is a problem with modification. (A) is implying that our ancestors greatly reduced their own numbers (this is incorrect because it was the event that greatly reduced ancestors). When we have an independent clause followed by a participle phrase (one that starts with a gerund and serves as an adjective clause), the participle phrase modifies the subject of the sentence.

In non-grammarese: 'ancestors' is the subject of the independent clause, 'at some time...' and because of the comma after event, we have the incorrect meaning. It was not the ancestors but an event that 'reduced their numbers.'

Therefore, we want to make sure that it is clear that 'event' is 'greatly reducing the numbers.' One way to fix that is by using the relative pronoun 'that.' In (B), we have 'an event that greatly reduced their numbers' that does a good job of correcting the error in (A).

Originally posted by jjindal on 07 Jul 2016, 00:27.
Last edited by jjindal on 07 Jul 2016, 03:40, edited 1 time in total.
Senior Manager
Joined: 23 Feb 2015
Posts: 443
GMAT 1: 720 Q49 V40
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

11 Sep 2016, 04:27
macjas wrote:
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"-at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

A at some time in the past our ancestors suffered an event, greatly reducing their numbers
B that at some time in the past our ancestors suffered an event that greatly reduced their numbers
C that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced
D some time in the past our ancestors suffered an event from which their numbers were greatly reduced
E some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

In the question, I can't understand WHY A is wrong? In A, didn't 'event' modify '' greatly reducing their numbers''?
In B, their indicates what? does it indicate ''anthropologists'', "people" or "ancestors
also, HOW an 'event' greatly reduced their number?
If I say:
They killed their father. [/i] Here, their is the pronoun of they. So, in the sentence B, .....event reduced their number. Here, their is plural but event is singular. I should not say that He killed their father. How the sentence matched its pronoun in B?
Thanks...
_________________

“The heights by great men reached and kept were not attained in sudden flight but, they while their companions slept, they were toiling upwards in the night.”
Social Network:

Retired Moderator
Joined: 14 Dec 2013
Posts: 2990
Location: Germany
Schools: HHL Leipzig
GMAT 1: 780 Q50 V47
WE: Corporate Finance (Pharmaceuticals and Biotech)
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

11 Sep 2016, 08:59
1
iMyself wrote:
macjas wrote:
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"-at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

A at some time in the past our ancestors suffered an event, greatly reducing their numbers
B that at some time in the past our ancestors suffered an event that greatly reduced their numbers
C that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced
D some time in the past our ancestors suffered an event from which their numbers were greatly reduced
E some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

In the question, I can't understand WHY A is wrong? In A, didn't 'event' modify '' greatly reducing their numbers''?
In B, their indicates what? does it indicate ''anthropologists'', "people" or "ancestors
also, HOW an 'event' greatly reduced their number?
If I say:
They killed their father. [/i] Here, their is the pronoun of they. So, in the sentence B, .....event reduced their number. Here, their is plural but event is singular. I should not say that He killed their father. How the sentence matched its pronoun in B?
Thanks...

1. Following is the official explanation for A:
The omission of that after the dash makes the function of the final clause unclear. The structure makes that clause appear to be an awkward and rhetorically puzzling separate assertion that the writer has appended to the prior claim about what the anthropologists believe. The agent or cause of reducing is unclear.

2. I do not understand your query "HOW an 'event' greatly reduced their number?" Why do you think that an event cannot reduce their number?

3. This query is also not clear - why do you consider that " He killed their father" is not correct? Why only "they" can kill their father and a single person (or a single event) can't?
Intern
Joined: 29 May 2015
Posts: 16
GMAT 1: 710 Q48 V38
GPA: 4
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

28 Dec 2016, 11:14
ChrisLele wrote:
In answer choice (A) there is a problem with modification. (A) is implying that our ancestors greatly reduced their own numbers (this is incorrect because it was the event that greatly reduced ancestors). When we have an independent clause followed by a participle phrase (one that starts with a gerund and serves as an adjective clause), the participle phrase modifies the subject of the sentence.

In non-grammarese: 'ancestors' is the subject of the independent clause, 'at some time...' and because of the comma after event, we have the incorrect meaning. It was not the ancestors but an event that 'reduced their numbers.'

Therefore, we want to make sure that it is clear that 'event' is 'greatly reducing the numbers.' One way to fix that is by using the relative pronoun 'that.' In (B), we have 'an event that greatly reduced their numbers' that does a good job of correcting the error in (A).

Why is the logic which he has mentioned not applicable to following question?
http://gmatclub[dot]com/forum/five-fledgling-sea-eagles-left-their-nests-in-western-130847.html
Using bringing would mean that eagles themselves are bringing down the numbers. But the fact is their action of leaving the nests is bringing down numbers.

Senior Manager
Joined: 06 Jul 2016
Posts: 372
Location: Singapore
Concentration: Strategy, Finance
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

30 Jul 2017, 04:50
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

Quote:
A at some time in the past our ancestors suffered an event, greatly reducing their numbers
D some time in the past our ancestors suffered an event from which their numbers were greatly reduced
E some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

'-' indicates that the author is going to rephrase what was mentioned in the first clause, so we need what comes after '-' to maintain parallelism => We require a 'that' immediately after the '-'
So A,D,E are out on this account.
A - States the ancestors reduced their own numbers
D - 'from which' is just plain awkward
E - 'so as to' indicates intent on the ancestors part and that was not the case.

Quote:
C that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced

This alters the meaning and it seems like the ancestors suffered an event in order to reduce their numbers and that is clearly incorrect. OUT!

Quote:
B that at some time in the past our ancestors suffered an event that greatly reduced their numbers

Maintains parallelism + 'that greatly...' correctly refers to 'an event'

_________________

Put in the work, and that dream score is yours!

Study Buddy Forum Moderator
Joined: 04 Sep 2016
Posts: 1247
Location: India
WE: Engineering (Other)
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

22 Aug 2017, 22:31
Hi GMATNinja generis GMATNinjaTwo

Can you help to differentiate between function of a hyphen and semicolon?
_________________

It's the journey that brings us happiness not the destination.

e-GMAT Representative
Joined: 02 Nov 2011
Posts: 2736
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

31 Jan 2018, 20:29
2
Hi GMATNinja generis GMATNinjaTwo

Can you help to differentiate between function of a hyphen and semicolon?

To begin with, this official sentence uses a dash and not a hyphen.

Now generally, both hyphens and semi-colons are used to connect two independent clauses.

However, in the correct answer choice of this official question, the hyphen is followed by a dependent clause.

Personally, I see this usage just as an exception to the rule, an atypical usage in a one-off case.

Hope this helps.
Thanks.
_________________

| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

Intern
Joined: 11 Jun 2017
Posts: 26
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

03 Feb 2018, 14:03
Comma+Ving will modify the nearest subject which is Ancestor in A. Hence, incorrect.

Comma+Ving can be the logical outcome of preceding clause, however not in this case. Because "scientist believed...." is NOT the logical outcome of reduced population. It is "the event" that reduces the population.
Intern
Joined: 19 Feb 2017
Posts: 42
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

30 Mar 2018, 09:11
egmat

1. I understand that "that" is needed after the "-" in order to maintain the parallelism between " that the genetic homogeneity evident in the world's people is the result of a "population bottleneck" and "that at some time in the past our ancestors suffered an event" as the portion after the "-" simply elaborates the portion before "-" and adds some more information. Please tell me if my understanding is correct.

2. However, please explain why is ", greatly reducing their numbers" wrong as I understand that ",-ing" modifies the preceeding clause and either presents the result of the action done in the preceeding clause or describes how the action is being done in the preceeding clause. Here, we can see that "greatly reducing their numbers" clearly presents the result of "past our ancestors suffered an event". Please explain
Intern
Joined: 19 Feb 2017
Posts: 42
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

30 Mar 2018, 09:22
egmat wrote:
kinjiGC wrote:
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

(A) at some time in the past our ancestors suffered an event, greatly reducing their numbers
(B) that at some time in the past our ancestors suffered an event that greatly reduced their numbers
(C) that some time in the past our ancestors suffered an event so that their numbers were greatly reduced,
(D) some time in the past our ancestors suffered an event from which their numbers were greatly reduced
(E) some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

Meaning: Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck". Population bottleneck – an event that occurred sometime back in the past which greatly reduced their numbers and thus our genetic variation.

Option A) “greatly reducing their numbers” – Verb-ing modifier comma separated, so presenting (modifying) more information about the preceding clause “at some time in the past our ancestors suffered an event” which is incorrect as the event reduced their numbers.

Option C) so that presents reason which is incorrect.

Option D) “from which” is incorrect. The correct sentence would be “some time in the past our ancestors suffered an event that greatly reduced their numbers”.

Option E) “so as” provides an intent.

My confusion is “that” in Option B)
that should replace “population bottleneck”
So the sentence becomes “population bottleneck at some time in the past our ancestors suffered an event that greatly reduced their numbers” – doesn’t look correct to me.

I know after the hyphen “-” the modifier comes which provides more information about the preceding noun.

Dear Kinjal,

The punctuation mark referred to by you is technically called a “dash”. Yes, it has a slightly less fancy name than the “hyphen”.

Moving on, the dash can be used in multiple ways. In the sentence at hand, it has been used to elaborate on what the author has mentioned before the dash. If you observe, the portion after the dash not only expands on the “bottleneck” bit but also on how the genetic homogeneity is the result of the mentioned bottleneck. Accordingly, if I were to draw a parallel structure it would be something on the following lines:

Mariana believes that altruism exists even in today’s day and age — that people can help others without any selfish motives is not an idea that is too unrealistic to exist in a society that thrives on rewarding individualism.

In the example sentence above, the portion after the dash reiterates the point stated earlier while elaborating a bit more on the same. Not only does it tell you more about the concept of altruism, as perceived by the author, but also about the whole statement made earlier. This is very similar to how the dash has been used in the correct choice of the question referred to by you in your post.

Of course, the above question does not limit the universe of the uses of this punctuation mark. You can also use the dash in various other forms, but the idea remains the same: to separate parts of the sentence while adding information. To enhance your understanding, you could refer to some other OG questions in your research - OG 13: Q#98 & Q#132.

Hope that helps!

Regards,
Neeti.

What is the difference between a dash and a hyphen? Do we need to bother about it in GMAT?
e-GMAT Representative
Joined: 02 Nov 2011
Posts: 2736
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

05 Apr 2018, 14:16
2
aviejay wrote:
egmat

1. I understand that "that" is needed after the "-" in order to maintain the parallelism between " that the genetic homogeneity evident in the world's people is the result of a "population bottleneck" and "that at some time in the past our ancestors suffered an event" as the portion after the "-" simply elaborates the portion before "-" and adds some more information. Please tell me if my understanding is correct.

2. However, please explain why is ", greatly reducing their numbers" wrong as I understand that ",-ing" modifies the preceeding clause and either presents the result of the action done in the preceeding clause or describes how the action is being done in the preceeding clause. Here, we can see that "greatly reducing their numbers" clearly presents the result of "past our ancestors suffered an event". Please explain

Hello aviejay,

Thank you for the query and the PM.

1. Yes, your understanding is correct.

2. It is true that the comma + verb-ing modifier presents either the how aspect or the result of the modified action. However, in modifying the preceding action, the comma + verb-ing modifier must also make sense with the doer of the modified action.

You are correct in saying that that comma + verb-ing modifier reducing seems to present the result of the action suffered. But, comma + reducing fails to make sense with doer - our ancestors - of the modified action.

Choice A seems to suggest that our ancestors suffered an event and as a result reduced their numbers. This meaning is certainly not logical.

From the context of the sentence, we know that the event that our ancestors suffered reduced their numbers.

Hope this helps.
Thanks.
_________________

| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

Intern
Joined: 19 Feb 2017
Posts: 42
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

05 Apr 2018, 21:32
egmat wrote:
aviejay wrote:
egmat

1. I understand that "that" is needed after the "-" in order to maintain the parallelism between " that the genetic homogeneity evident in the world's people is the result of a "population bottleneck" and "that at some time in the past our ancestors suffered an event" as the portion after the "-" simply elaborates the portion before "-" and adds some more information. Please tell me if my understanding is correct.

2. However, please explain why is ", greatly reducing their numbers" wrong as I understand that ",-ing" modifies the preceeding clause and either presents the result of the action done in the preceeding clause or describes how the action is being done in the preceeding clause. Here, we can see that "greatly reducing their numbers" clearly presents the result of "past our ancestors suffered an event". Please explain

Hello aviejay,

Thank you for the query and the PM.

1. Yes, your understanding is correct.

2. It is true that the comma + verb-ing modifier presents either the how aspect or the result of the modified action. However, in modifying the preceding action, the comma + verb-ing modifier must also make sense with the doer of the modified action.

You are correct in saying that that comma + verb-ing modifier reducing seems to present the result of the action suffered. But, comma + reducing fails to make sense with doer - our ancestors - of the modified action.

Choice A seems to suggest that our ancestors suffered an event and as a result reduced their numbers. This meaning is certainly not logical.

From the context of the sentence, we know that the event that our ancestors suffered reduced their numbers.

Hope this helps.
Thanks.

This totally helps Shraddha. Thanks a lot
Manager
Joined: 27 Mar 2014
Posts: 81
Schools: ISB '19, IIMA , IIMB
GMAT 1: 660 Q49 V30
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

19 May 2018, 23:22
sayantanc2k wrote:
deepak268 wrote:
egmat
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"-at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

I still dont get why A is not correct ?
"ing" plays 2 role first is describing the action with subject and second it can be an effect of a cause mentioned earlier in the clause.
here why cant "greatly reducing their numbers and thus our genetic variation" be an effect of " ancestors suffering from event "
It can mean " ancestors suffered from event and thus suffering from that event led to reducing their....blabla " clear cause and effect.
if "ing" can play second role clearly why one has to check for the first role "ing" plays( i.e. describing with subject) ??
If option A is incorrect it has to be some other reason.
thanks

Without "that", the latter clause ( " at some time....greatly reduced their numbers") does not have much meaningful bearing to the first clause as the author intended. It is required to establish that the scientists believe even the latter clause and hence "that" is required to be repeated.

In that case , dont be require an "and" b/w "believe that the genetic homogeneity......" and " that at some time....greatly reduced their numbers"

pls. help
Intern
Joined: 17 Apr 2018
Posts: 32
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

06 Jul 2018, 18:13
A - greatly reducing modifies Ancestors --> distorts.
c,d - Root word "reduced" should come before their numbers so that it
can be parallel for both "their numbers" and "genetic variation"
E - "so as to" distorts the meaning

_________________

Let's share some kudos together.

Manager
Joined: 02 Aug 2017
Posts: 67
Concentration: Strategy, Nonprofit
Schools: ISB '20
GPA: 3.71
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

13 Jul 2018, 07:18
It might be helpful to understand the difference between commonly confused words.
Sometimes is a one-word adverb that means “occasionally” or “now and then.”
Sometimes I just don’t understand what that man is saying.

When some time is two words, it refers to a span of time. In fact, it often means “a long time.”
For some time, humans have known that the world is round.

When you use sometime as an adverb, it refers to an unspecified point in time. It doesn’t refer to a span of time—that’s what some time is for.
I’ll get around to finishing that book sometime.
Albert, a sometime cab driver, now flies aeroplanes for a living.

At some time = sometime
_________________

Everything is in flux, nothing stays still

MGMAT1 :590 Q42 V30 (07/07/18)
VERITAS :660 Q48 V33 (16/07/18)
GMATPREP1 :690 Q46 V36 (22/07/18)
GMATPREP2 :740 Q51 V39 (06/08/18)
ECONOMIST :740 Q49 V44 (11/08/18)
KAPLAN :690 Q49 V36 (17/08/18)
PRINCETON :690 Q48 V38 (26/08/18)
MGMAT2 :720 Q43 V45 (02/09/18)

Director
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 532
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

31 Jul 2018, 08:44
Top Contributor
macjas wrote:
The Official Guide for GMAT Review 2017

Practice Question
Question No.: SC 736
Page: 695

Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

(A) at some time in the past our ancestors suffered an event, greatly reducing their numbers

(B) that at some time in the past our ancestors suffered an event that greatly reduced their numbers

(C) that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced

(D) some time in the past our ancestors suffered an event from which their numbers were greatly reduced

(E) some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

(A) at some time in the past our ancestors suffered an event, greatly reducing their numbers AWAKWARD

(B) that at some time in the past our ancestors suffered an event that greatly reduced their numbers CORRECT

(C) that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced AWAKWARD AND AT IS REQUIRED AFTER THAT

(D) some time in the past our ancestors suffered an event from which their numbers were greatly reduced WICH DOESN'T HAVE PROPER REFERENT

(E) some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly SO AS TO IS AWAKWARD
_________________

Collections:-
PSof OG solved by GC members: http://gmatclub.com/forum/collection-ps-with-solution-from-gmatclub-110005.html
DS of OG solved by GC members: http://gmatclub.com/forum/collection-ds-with-solution-from-gmatclub-110004.html
100 GMAT PREP Quantitative collection http://gmatclub.com/forum/gmat-prep-problem-collections-114358.html
Collections of work/rate problems with solutions http://gmatclub.com/forum/collections-of-work-rate-problem-with-solutions-118919.html
Mixture problems in a file with best solutions: http://gmatclub.com/forum/mixture-problems-with-best-and-easy-solutions-all-together-124644.html

Verbal Forum Moderator
Status: Greatness begins beyond your comfort zone
Joined: 08 Dec 2013
Posts: 2108
Location: India
Concentration: General Management, Strategy
Schools: Kelley '20, ISB '19
GPA: 3.2
WE: Information Technology (Consulting)
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

28 Oct 2018, 20:36
macjas wrote:
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

(A) at some time in the past our ancestors suffered an event, greatly reducing their numbers -- Can we reject this option because we are joining 2 independent clauses using — ?

(B) that at some time in the past our ancestors suffered an event that greatly reduced their numbers

(C) that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced -- usage of so that

(D) some time in the past our ancestors suffered an event from which their numbers were greatly reduced - we need a preposition with some time ; “from which” construction stands for “their numbers were greatly reduced from the event”. Clearly, the numbers were reduced not FROM the event but BY the event.

In general, “sometime” means “at some point”, and “some time” means “a period of time”.

(E) some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly, - we need a preposition with some time ; “so as to” indicates purpose. This option illogically means that the ancestors suffered with an intention to reduce their numbers.

1. Is the punctuation that follows the phrase "population bottleneck" is a hyphen or a dash? Can you list uses of both of them?

2. Can we reject option A because we are joining 2 independent clauses using — ?

3. In option A, DOES verb-ing modifier need to make sense with the subject of the preceding clauses our ancestors?

At some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation. -- here verb-ing modifier reducing does explain the entire action of preceding clause but does not make sense with the subject.

I dropped the bags onto the floor, scaring the dogs---> here I did not directly scare the dogs but my action of dropping the bags did.

As per the official question in the following link -

https://gmatclub.com/forum/between-14-0 ... l#p1868115

Between 14,000 and 8,000 b.c. the ice cap that covered northern Asia, Europe, and America began to melt, uncovering vast new areas that were to be occupied by migrating peoples moving northward.

An observation from this question is that the verb-ing ‘uncovering’ does not make sense with the subject ‘ice cap’: ice cap didn’t do the action of ‘uncovering’. ‘Uncovering of the areas’ happened on its own as a direct consequence of ‘melting’. Thus, we can learn from this question that in ‘comma+verb-ing structure’, verb-ing doesn’t need to always make sense with the subject as long as it provides a direct consequence of the action of the clause.

AjiteshArun , GMATNinja , MagooshExpert , VeritasPrepBrian, GMATGuruNY , VeritasKarishma , DmitryFarber , RonPurewal , ChiranjeevSingh , other experts - please enlighten
_________________

When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry Ford
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long
+1 Kudos if you find this post helpful

SC Moderator
Joined: 23 Sep 2015
Posts: 1353
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

01 Nov 2018, 16:08
Skywalker18 - ah! I used to think these two are same - hyphen and a dash (now I know there are 2 type of dash, m dash and n dash, This one is em dash.), Apparently Not. Is their usage tested beyond what we have in this question ?
_________________

Thanks!
Do give some kudos.

Simple strategy:
“Once you’ve eliminated the impossible, whatever remains, however improbable, must be the truth.”

GMAT Ninja YouTube! Series 1| GMAT Ninja YouTube! Series 2 | How to Improve GMAT Quant from Q49 to a Perfect Q51

My Notes:
Reading comprehension | Critical Reasoning | Absolute Phrases | Subjunctive Mood

EMPOWERgmat Instructor
Joined: 23 Feb 2015
Posts: 370
Re: Some anthropologists believe that the genetic homogeneity  [#permalink]

### Show Tags

07 Nov 2018, 11:19
Hello Everyone!

While it seems that the original question came with a pretty thorough explanation, let's see if we can figure out how you would tackle this question if you found in on the GMAT! To get started, let's look at the original question, and highlight any major differences in orange:

Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

(A) at some time in the past our ancestors suffered an event, greatly reducing their numbers
(B) that at some time in the past our ancestors suffered an event that greatly reduced their numbers
(C) that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced
(D) some time in the past our ancestors suffered an event from which their numbers were greatly reduced
(E) some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

After a quick glance over the options, there are a couple things we can focus on:

1. at some time / that at some time / that sometime / some time
2. Their endings (intended meaning)

Let's start by taking a closer look at #1 on our list: how to begin! We know that the phrase starts directly after an em dash, so we need to follow the rules concerning em dashes. In this sentence, the em dash is used to show that what follows is a more detailed explanation of a "population bottleneck." You could replace the em dash with the phrase "in other words" and it should still make sense because both the original explanation and the "rewording" of it should be parallel:

Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

(A) at some time in the past our ancestors suffered an event, greatly reducing their numbers
(B) that at some time in the past our ancestors suffered an event that greatly reduced their numbers
(C) that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced
(D) some time in the past our ancestors suffered an event from which their numbers were greatly reduced
(E) some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

We can eliminate options A, D, & E because they don't have the word "that" to create a parallel structure to the original explanation.

Now that we only have 2 options to choose from, let's add in the rest of the sentence and check for other problems:

(B) Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—that at some time in the past our ancestors suffered an event that greatly reduced their numbers and thus our genetic variation.

This is CORRECT! It uses parallel wording by starting both explanations with the word "that." It also uses parallel structure to list the two things that were greatly reduced: their numbers / our genetic variation. It uses the structure "greatly reduced X and Y," where X and Y were both written using parallel structure (pronoun + noun).

(C) Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced and thus our genetic variation.

This is INCORRECT! While it does use parallelism to start both explanations with "that," there is a parallelism problem later on:

their numbers were greatly reduced and thus our genetic variation = X was greatly reduced and Y = NOT PARALLEL

To fix it, we would have to repeat the verb:

their numbers were greatly reduced and thus our genetic variation was greatly reduced = X was greatly reduced and Y was greatly reduced = PARALLEL

There you have it - option B is the correct choice because it uses parallel structure throughout the sentence!

Don't study for the GMAT. Train for it.
_________________

"Students study. GMAT assassins train."

★★★★★ GMAT Club Verified Reviews for EMPOWERgmat & Special Discount

GMAT Club Verbal Advantage EMPOWERgmat Critical Reasoning Question Pack

Re: Some anthropologists believe that the genetic homogeneity &nbs [#permalink] 07 Nov 2018, 11:19

Go to page   Previous    1   2   [ 40 posts ]

Display posts from previous: Sort by