Sentence Correction

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,

nahid078 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,

Option A:
1.we need a connector 'that' after believe because the sentence is continuing to talk about the belief.
2.Reducing is a VERB-ing modifier- Clause,Verbing modifies the preceding and makes meaning with subject of the preceding clause.Here "ancestors" is the subject of the preceding clause.Ancestors are reducing --is nonsensical ..Its the event.
Option B:Correct
Option C:so that--implies the ancestors suffered the event intentionally--which is wrong
Option D:
1.Misses 'at; prepostion before sometime.
2.Modifier --from which their numbers were greatly reduced..implies that the event was reason..rather intended meaning is the result of event ..
Option E:
that incorrectly refers to some time in the past
also misses prepostion

Hope it helps!!

prabsahi wrote:

nahid078 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,

Option A:
1.we need a connector 'that' after believe because the sentence is continuing to talk about the belief.
2.Reducing is a VERB-ing modifier- Clause,Verbing modifies the preceding and makes meaning with subject of the preceding clause.Here "ancestors" is the subject of the preceding clause.Ancestors are reducing --is nonsensical ..Its the event.
Option B:Correct
Option C:so that--implies the ancestors suffered the event intentionally--which is wrong
Option D:
1.Misses 'at; prepostion before sometime.
2.Modifier --from which their numbers were greatly reduced..implies that the event was reason..rather intended meaning is the result of event ..
Option E:
that incorrectly refers to some time in the past
also misses preposition

Hope it helps!!

Thanks for the great explanation. But i have a question. How to understand the sentence is continuing to talk about the belief? What does (-) indicate?

oh another question. Can you please clarify the meaning of "as to"?

Thanks again

nahid078 wrote:

prabsahi wrote:

nahid078 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,

Option A:
1.we need a connector 'that' after believe because the sentence is continuing to talk about the belief.
2.Reducing is a VERB-ing modifier- Clause,Verbing modifies the preceding and makes meaning with subject of the preceding clause.Here "ancestors" is the subject of the preceding clause.Ancestors are reducing --is nonsensical ..Its the event.
Option B:Correct
Option C:so that--implies the ancestors suffered the event intentionally--which is wrong
Option D:
1.Misses 'at; prepostion before sometime.
2.Modifier --from which their numbers were greatly reduced..implies that the event was reason..rather intended meaning is the result of event ..
Option E:
that incorrectly refers to some time in the past
also misses preposition

Hope it helps!!

Thanks for the great explanation. But i have a question. How to understand the sentence is continuing to talk about the belief? What does (-) indicate?

oh another question. Can you please clarify the meaning of "as to"?

Thanks again

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.

The highlighted sentence in bold starts with that..blah blah.This is a modifying clause.Remove this and you have the answer

GMATGuruNY 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,

A COMMA + VERBing modifier is attributed to the SUBJECT of the preceding clause.
In A, reducing seems to refer to our ancestors, implying that OUR ANCESTORS were greatly reducing their numbers.
Not the intended meaning: our ancestors did not reduce their own numbers.
The intended meaning is that an EVENT greatly reduced their numbers.
Eliminate A.

So that (in C) and so as (in E) imply PURPOSE.
The result is a strange meaning: that our ancestors suffered for the PURPOSE of reducing their numbers.
Not the intended meaning.
Eliminate C and E.

In D, which seems to refer to an event, implying that our ancestors' numbers were reduced FROM an event -- a nonsensical meaning.
Eliminate D.

The correct answer is B.

Thanks a lot,Guru.
I have 2 question?

does "as to" indicate purpose?

I am confused with the use of "The" in option A.

Would you please explain?

NB: you didn't see my PM

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!


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