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# Scientists have recently found evidence that black holes—regions of sp

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Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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Updated on: 18 Apr 2019, 22:52
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Masterscorp

The basic concept of using that in two-part sentences.
If Something does two things, those things must be presented parallelly in structure and meaning joined by the introducing connector 'that.' For example. we may say that
<John reported to his wife that he got 800 in GMAT and that it all happened because of her help >
We need the connector that because of the two equally important things.
Rule No 2. If you are reporting only one thing and if the second part is n independent event not related to the first, then the golden rule is that there must be a comma before the word 'and' to forewarn that a new clause is about to begin
In my example, we might re-write the whole thing if we drop the 'that'.
John reported to his wife that he got 800 in GMAT,
and it all happened because of her help. But still one can see the disconnect in that legitimately grammatical clause
In other words, when we write compound sentences with two independent terms, then there must necessarily be a comma before the fanboys conjunction

I fully agree with Masterscorp
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Originally posted by daagh on 09 Apr 2018, 08:52.
Last edited by daagh on 18 Apr 2019, 22:52, edited 2 times in total.
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QOTD: Scientists have recently found evidence that black holes  [#permalink]

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25 May 2018, 07:14
1
souvik101990 wrote:

Verbal Question of The Day: Day 260: Sentence Correction

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Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to

(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of

(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

Every question of the day will be followed by an expert reply by GMATNinja in 12-15 hours. Stay tuned! Post your answers and explanations to earn kudos.

GMATNinja what function does dash sign have in this senntence ?

Scientists have recently found evidence that black holesregions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from themprobably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

i chose actually D ....i thought "nothing" refers to 'exists"

you can answer this question on the weekend when you are in better mood
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Re: QOTD: Scientists have recently found evidence that black holes  [#permalink]

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25 May 2018, 10:57
2
dave13 wrote:

GMATNinja what function does dash sign have in this senntence ?

Scientists have recently found evidence that black holesregions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from themprobably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

i chose actually D ....i thought "nothing" refers to 'exists"

you can answer this question on the weekend when you are in better mood

Hello dave13,

Although this question is not for me, I would be glad to help you out with this.

In this official sentence, the two dashes have been used as a comma pair to enclose some extra description, in this case the description of the black holes.

As far as your choosing Choice D as the correct answer is considered, I would say that Choice D and E are the easiest choices to reject because the SV number agreement error is the easiest to spot.

Hope this helps.
Thanks.
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Re: QOTD: Scientists have recently found evidence that black holes  [#permalink]

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01 Jun 2018, 19:46
3
dave13 wrote:
souvik101990 wrote:

Verbal Question of The Day: Day 260: Sentence Correction

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Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to

(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of

(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

Every question of the day will be followed by an expert reply by GMATNinja in 12-15 hours. Stay tuned! Post your answers and explanations to earn kudos.

GMATNinja what function does dash sign have in this senntence ?

Scientists have recently found evidence that black holesregions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from themprobably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

i chose actually D ....i thought "nothing" refers to 'exists"

you can answer this question on the weekend when you are in better mood

I know that this doesn't really answer your question (and somebody else already answered it, anyway)... but here's a video about punctuation on GMAT SC: https://www.youtube.com/watch?v=JLAJ_drP8UM.

The punchline is basically that there's no real reason to worry much about the exact rules surrounding dashes, partly because English-language editors (I used to be one!) and style experts don't remotely agree on the best ways to use dashes. If you pick up a bunch of the world's best publications written in English, you'll see a whole bunch of different opinions about how to use dashes correctly -- and about whether they should be used at all. Some editors hate them.

And on the GMAT? You'll see dashes, but they're never really the deciding factor, partly because I don't think that the GMAT wants to try to settle a broader debate about dashes. On official questions, there are always more important issues in the sentence, and you can always answer the question without really worrying about whether a dash was the best choice of punctuation.

I hope this helps!
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Re: QOTD: Scientists have recently found evidence that black holes  [#permalink]

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01 Jun 2018, 20:03
1
IMO ans is B.

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to incorrect, need 'that' after 'and' for parallelism

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of correct

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to incorrect, illogical comparison between mass and galaxy

(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of incorrect, SV agreement 'black holes' is a plural noun

(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of incorrect, same as D
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Re: QOTD: Scientists have recently found evidence that black holes  [#permalink]

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21 Aug 2018, 03:01
4
The sentence says that scientists have recently found evidence for two things.

The black holes probably exist at the core of nearly all galaxies
The mass of each black hole is proportional to its host galaxy
Please note that the sentence also provides a lot of information about black holes within two dashes. You can read the idea between the dashes. However, the more important thing is that when you start reading after the closing dash, read as if the dashes and everything contained within the dashes weren’t there. In other words, you shouldn’t get lost in the deluge of information in the dashes and should be able to connect the part of the sentence that appears after the dashes to the part before the dashes.

There are two problems with this sentence:

“That” is missing after ‘and’. To make it clear that the evidence suggests “that the mass of each…”, we need to place ‘that’ before “the mass of each…”. Without ‘that’, it may seem like another independent clause having nothing to do with evidence.
The second problem is with the meaning. It doesn’t make sense to say that the mass of X is proportional to a galaxy. Probably, we mean to say that the mass of X is proportional to the mass of a galaxy. Therefore, the second part of the sentence should be modified to say “proportional to the mass of its host galaxy”. Please note that when we are evaluating the options, we need to be flexible i.e. even though it seems to be “proportional to the mass of its host galaxy”, it may eventually turn out to be “proportional to the size of its host galaxy”.
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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07 Dec 2018, 12:36
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amatya wrote:
Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to

(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of

(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

First, we can IGNORE the appositive phrase "regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them"

So, we can read the original sentence as: Scientists have recently found evidence that black holes exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

Scanning the answer choices, we see EXIST vs EXISTS
Since the verb must agree with BLACK HOLES (plural), we need the plural verb EXIST.
ELIMINATE D and E

Next, notice that the scientists discovered two things:
#1) that black holes exist at the core of nearly all galaxies
#2) the mass of each black hole is proportional to its host galaxy.

Item #1 is a relative clause beginning with THAT.
So, to maintain parallelism, item #2 must also begin with THAT

In other words, we need: Scientists have recently found evidence THAT black holes exist at the core of nearly all galaxies and THAT the mass of each black hole is proportional to its host galaxy.
ELIMINATE A.

We're left with answer choices B and C
B) Scientists have recently found evidence that black holes exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of its host galaxy.
We are comparing the MASS of each black hole to THAT (aka the MASS) of its host galaxy.
Since we're logically comparing masses, we can KEEP B for now

C) Scientists have recently found evidence that black holes exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to its host galaxy.
Here, we're comparing the MASS of each black hole to a HOST GALAXY.
This comparison makes no sense.
ELIMINATE C

By the process of elimination, the correct answer is B

Cheers,
Brent
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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25 Dec 2018, 01:31
"that the mass of each black hole is proportional to....."
Can anyone please explain to me the function of "that" in the sentence?
and could we omit "that" in the sentence?
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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04 Apr 2019, 12:36
1
Hello Everyone!

This is a great example of a GMAT question that focuses on parallelism and subject-verb agreement! Let's start by taking a quick look at the original question, and highlighting any major differences between the options in orange:

Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to
(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of
(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to
(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of
(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

After taking a quick glance over the options, 2 major differences jumped out:

1. exist vs. exists (subject-verb agreement)
2. to vs. to that of (parallelism)

Let's start with #1 on our list: subject-verb agreement. If we look at the entire sentence, we should be able to identify the subject that matches up with the verb "exist/exists" pretty quickly:

Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

Since the subject "black holes" is plural, we need to make sure the verb we use is also plural:

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to
(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of
(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to
(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of
(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

We can eliminate options D & E because the singular verb "exists" doesn't match the plural subject "black holes." Pretty easy, right?

Now let's tackle #2 on our list: parallelism. This sentence is comparing two items, and we need to make sure that they are parallel in type. To make this easier to spot, we'll add the rest of the comparison to each option for you. Here's how they break down:

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

This is INCORRECT because it's comparing mass to galaxy, which aren't the same thing at all!

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of its host galaxy.

This is CORRECT! It's clear that by adding in the phrase "that of," we're now comparing the mass of each black hole to the mass of its host galaxy, which is parallel.

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to its host galaxy.

This is INCORRECT because it's trying to compare mass to galaxies, which aren't parallel.

There you have it - option B is the correct choice! It uses proper parallel structure to compare two items, and it doesn't have any subject-verb agreement issues!

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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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09 Apr 2019, 06:17
Quote:
Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

Hi,
Two most popular issues in the original sentence: Parallelism & comparison.
Parallelism: ...found evidence that black holes ...., and that the mass.....
Comparison: the mass of each black hole is proportional to its galaxy

Whichever option corrects above stated issues will be the correct option. Lets pick the best choice:

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to: Out, reason stated above.

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that[mass] of: Keep, reject the rest on solid grounds.

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to its galaxy: Mass to galaxy; OUT

(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of

(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

B is our answer.
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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18 Apr 2019, 21:16
2
Quote:
Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to
(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of
(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to
(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of
(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

OG16 SC128

-Three things i observed
1. S-V agreement(black holes - exist/exists)
2. Parallelism(and)
3. Meaning(recent discovery v/s fact)
4. Comparison(Mass of black holes to host galaxy)

Based on S-V agreement D & E are out(plural subject and singular verb). Parallelism and Meaning are interdependent here since parallelism create a different meaning(that Black holes existence is a recent discovery and proportionality of black hole mass to host galaxy is a known fact which is not) which is vague certainly because without knowing about apples one can't say anything about its taste. This becomes easier to understand by hiding the sentence part between two dashes. Lastly, the Comparison just nails things down to one option i.e. B.

Option-(B) Correct.

Hope this is clear enough understanding on my part though i first saw comparison and then realized the meaning of sentence, hence marked B. Definitely, would want to know/see the meaning as early as possible. Trying my best.

Comments and inputs are most welcomed.

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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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18 Apr 2019, 22:14
1
lnm87 wrote:
This is my first post since joining this wonderful platform which is helping many lost candidates. On a journey to better my verbal #MyfirstGMATclubpost
You did a good job on this question. Keep it up.
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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19 Apr 2019, 00:46
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Top Contributor
INM

Welcome to the forum and wonderful and masterly analysis. One more kudos to you.

May I take your okay to make some observations on your analysis? I presume so.
Quote:
1. -Three things i observed
1. S-V agreement(black holes - exist/exists)
2. Parallelism(and)
3. Meaning(recent discovery v/s fact)
4. Comparison(Mass of black holes to host galaxy)

Based on S-V agreement D & E are out(plural subject and singular verb). Parallelism and Meaning are interdependent here since parallelism create a different meaning(that Black holes existence is a recent discovery and proportionality of black hole mass to host galaxy is a known fact which is not) which is vague certainly because without knowing about apples one can't say anything about its taste. This becomes easier to understand by hiding the sentence part between two dashes. Lastly, the Comparison just nails things down to one option i.e. B.

Option-(B) Correct.

I think you have observed in fact four things. Let me now change the order of the observations.

1. S.V agreement --- D and E are gone.

2. comparison ---------A and C gone

3. Meaning ------------ Nothing more to discard. This point is academic and in fact redundant.
4. Parallelism: ------- Same treatment as for point 3.

I am not saying in the least that meaning and parallelism are not important. However, in the context, one may stop at point two and if one can afford the luxury of spare time in the exam, one may verify with the other points.

My comments are related only to the strategy for GMAT and not intended against one's quest for knowledge.
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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27 May 2019, 08:14
Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

Analysis: We can skip '—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—' to make sentence easier. Therefore, sentc becomes:
'Scientists have recently found evidence that black holes probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy'

1. We can clearly see that two clauses 'black holes probably exist at the core of nearly all galaxies' and 'the mass of each black hole is proportional to its host galaxy' ain't parallel. As one talks abt 'black holes' and another talks abt ' the mass of each black hole'. So the parallel str is what scientist have found. Hence we need 'that' in order to make two findings parallel.
2. 'black holes' is plural so plural verb 'exist' is correct
3. 'the mass of each black hole' needs to be compared with 'mass of its host galaxy' and not 'host galaxy'

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to - 1,3

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of - Corrects all the errors discussed above

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to - 3

(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of - 2

(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of - 1,2

Hence B
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Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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24 Jun 2019, 00:24
1
GMATNinja wrote:
Quote:
(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to

(A) doesn’t seem all that bad. It certainly sounds fine, but there’s a problem with the parallelism and meaning.

Before we get into that, consider the following:

• I believe that Santa Claus is real and that the Knicks will win the 2018 NBA title. → We have two parallel phrases (subordinate clauses, if you like jargon) that begin with “that.” And that’s great: it’s super-clear that these are two things that I believe.
• I believe that Santa Claus is real and the Knicks will win the 2018 NBA title. → Now the parallelism is different. Without “that”, we just have two parallel, independent clauses: “I believe that Santa Claus is real” and “the Knicks will win the NBA title.” That changes the meaning: now, the sentence doesn’t connect “I believe” with “the Knicks will win the NBA title.” And it seems that the latter clause is a fact, rather than something I BELIEVE is true.

We have a similar situation in (A). On both sides of the “and”, we have full, independent clauses:

• “Scientists have recently found evidence that black holes exist at the core of nearly all galaxies…”
• ”…the mass of each black hole is proportional to its host galaxy.”

Here’s the problem: the second independent clause is just a completely separate statement. The second clause (“the mass of each black hole is proportional…”) seems to be a separate fact; without “that” in front of that clause, it’s not clear that scientists have found evidence to support the statement. The statement is just a separate thing.

There’s also a comparison problem with (A). We have “the mass of each black hole is proportional to its host galaxy”, which is illogical: the mass of each black hole might be proportional to the mass of its host galaxy, but it’s weird to suggest that the mass is somehow proportional to the galaxy itself.

So we have a couple of (admittedly somewhat subtle) reasons to eliminate (A).

Quote:
(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of

Now the parallelism is better: “Scientists have found evidence that black holes… probably exist… and that the mass of each black hole is proportional…” Cool: now it’s clear that scientists have found evidence for these two things.

The other thing that should jump out at you is the phrase “that of.” “That” is a singular pronoun in this situation (more on “that”), and it clearly refers back to “mass” in (B). And that’s great: “…the mass of each black hole is proportional to the mass of its host galaxy.”

So we can keep (B).

Quote:
(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to

(C) is identical to (B), except that the phrase “that of” is missing. And as we mentioned in the explanation for (A), that’s a problem: literally, (C) says that “the mass of each black hole is proportional to its host galaxy”, and that’s not quite right: the mass of the black hole is proportional to the mass of the host galaxy – not to the galaxy itself.

So (C) is out.

Quote:
(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of

(D) is identical to (B), except for one little problem: “Scientists have found evidence that black holes… exists…” That’s a wonderfully clear subject-verb error, and we can eliminate (D).

Quote:
(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

(E) has exactly the same subject-verb error as (D): “Scientists have found evidence that black holes… exists…” Plus, the parallelism is a problem, because “and” isn’t followed with “that” – see the explanation for (A) for more on this issue.

So (E) is out, and (B) is our answer.

Hello GMATNinja,

Can you help me understand what "its" refer to in the non-underlined part of the last 3 words?

I was confused b/w Black hole & Mass. In the same option B, we have black hole singular too.

I rewrote the second || that clause of option B as " that the mass of each black hole is proportional to that(mass) of its(black hole's) host galaxy."

Considering this, I eliminated option B.

After reading your explanation, i understand that I was wrong but how do we ensure that we do not repeat such mistake?
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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26 Jun 2019, 18:53
Quote:
Hello GMATNinja,

Can you help me understand what "its" refer to in the non-underlined part of the last 3 words?

I was confused b/w Black hole & Mass. In the same option B, we have black hole singular too.

I rewrote the second || that clause of option B as " that the mass of each black hole is proportional to that(mass) of its(black hole's) host galaxy."

Considering this, I eliminated option B.

After reading your explanation, i understand that I was wrong but how do we ensure that we do not repeat such mistake?

I'm worried that I don't quite understand your question -- it sounds like your interpretation of the pronouns in (B) was 100% correct!

It makes sense to write that the mass of a black hole is proportional to the mass of the black hole's host galaxy. We know that "its" has to refer to a singular antecedent and the closest singular antecedent here is "black hole."

Did you somehow get confused about the meaning, and decide that it was illogical somehow?

Sorry that I'm not more helpful on this, but it sounds like you were on the right track.
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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26 Jun 2019, 21:27
GMATNinja wrote:
Quote:
Hello GMATNinja,

Can you help me understand what "its" refer to in the non-underlined part of the last 3 words?

I was confused b/w Black hole & Mass. In the same option B, we have black hole singular too.

I rewrote the second || that clause of option B as " that the mass of each black hole is proportional to that(mass) of its(black hole's) host galaxy."

Considering this, I eliminated option B.

After reading your explanation, i understand that I was wrong but how do we ensure that we do not repeat such mistake?

I'm worried that I don't quite understand your question -- it sounds like your interpretation of the pronouns in (B) was 100% correct!

It makes sense to write that the mass of a black hole is proportional to the mass of the black hole's host galaxy. We know that "its" has to refer to a singular antecedent and the closest singular antecedent here is "black hole."

Did you somehow get confused about the meaning, and decide that it was illogical somehow?

Sorry that I'm not more helpful on this, but it sounds like you were on the right track.

Yes, I was confused with the meaning thinking that it is illogical.

Posted from my mobile device
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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26 Sep 2019, 08:54
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amatya wrote:
Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

(A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to

(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of

(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to

(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of

(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

I managed to do it in less than a minute so sharing my approach.

Original Sentence :

Scientists have recently found evidence that black holes—regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them—probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

Just ignore the part in red. It gives additional information. We will come back if needed.

So now it reads :
Scientists have recently found evidence that black holes probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

Now since we are talking about black holes and not just a black hole we need exist and not exists.

Quote:
(D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of
(E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of

Notice that there is a that in the non underlined portion. So there should be a that after the "and" too. Hence A is incorrect.

Quote:
(B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of
(C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to

The only difference is "that of" and we need it. Because we are comparing mass of each black hole to mass of its host galaxy. We need "that of"
Hence B.

Thank you!
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Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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11 Oct 2019, 02:52
Dear GMATNinja, I think up another reason to eliminate option C: the use of the comma after "galaxy" is incorrect because if we have only 2 clauses after "found evidence that", we don't need to have a comma before "and that". The sentence should read: "Scientists have recently found evidence that black holes probably exist at the core ... and that the mass of each black hole is proportional to its host galaxy".

However, if the list consists of 3 or more items, a comma is needed: A, B, and C.

Is my thinking correct?
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Re: Scientists have recently found evidence that black holes—regions of sp  [#permalink]

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19 Oct 2019, 06:31
Tracy95 wrote:
Dear GMATNinja, I think up another reason to eliminate option C: the use of the comma after "galaxy" is incorrect because if we have only 2 clauses after "found evidence that", we don't need to have a comma before "and that". The sentence should read: "Scientists have recently found evidence that black holes probably exist at the core ... and that the mass of each black hole is proportional to its host galaxy".

However, if the list consists of 3 or more items, a comma is needed: A, B, and C.

Is my thinking correct?

It's true that if you have two modifying clauses connected by "and" you usually won't find a comma between them, but this isn't an ironclad rule, so in general, I'd be wary of eliminating an answer choice on this basis.

That's especially true in this case, since we have an illogical comparison in (C): the mass of the black hole should be proportional to the mass of the host galaxy, not to the galaxy itself.

More generally, you'll want to eliminate answer choices based on definitive errors, and the absence or presence of a comma is almost never a definitive error. So if you ever find yourself agonizing over whether a comma is used appropriately, look for other more concrete issues to use as decision points instead.

I hope that helps!
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Re: Scientists have recently found evidence that black holes—regions of sp   [#permalink] 19 Oct 2019, 06:31

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