Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period. (A) which, causing plant and animal extinctions, marks (B) which caused the plant and animal extinctions marking (C) and causing plant and animal extinctions that mark (D) an event that caused plant and animal extinctions, which marks (E) an event that caused the plant and animal extinctions that mark Here is my question: In options E and D, how is the appositive grammatically right, shouldn't the appositive set next to the noun that it's modifying, in this case what is (an event) actually modifying because if it's modifying north america, then it wouldnt be right need help plz SC SC4344 Verbal Review.jpg https://www.nytimes.com/1996/11/26/science/asteroid-s-shallow-angle-may-have-sent-inferno-over-northern-kill-zone.html SCIENTISTS have reconstructed an almost blow-by-blow account of the catastrophe that overtook the Earth 65 million years ago at the end of the age of dinosaurs. They believe a marauding asteroid bigger than Mount Everest slammed into Earth at a shallow angle, blasting an inferno of white-hot debris for thousands of miles across the young continent of North America and turning its mountains and valleys into killing fields. The incinerated plants and animals were the first victims in a wave of global extinction that eventually erased hundreds of thousands of species from the face of Earth, marking the end the Cretaceous Period .

I think the confusion is that there are two different versions of this question: The first one appears on this thread; the second appears in multiple editions of the verbal guide. The first version doesn't really have a subject-verb issue at all, for the reasons you mentioned. It's only the second version that does. Here's the excerpt from my explanation above, applied only to that second version: In the second version, "which marks..." seems to modify the nearest noun, "extinctions." And that would be a clear subject-verb error. Sure, I suppose you could argue that the phrase "which marks..." modifies the entire preceding mess (" an event that caused plant and animal extinctions"), but at minimum, that's confusing, because "an event" is so far back in the sentence. (E) is much clearer in that version of the question. I hope that helps at bit!

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12 Sep 2019, 10:58

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GMATNinja

This one isn't too awful, compared to some of the QOTDs we'll inflict on you later this week. For the most part, this is a nice story about straightforward uses of "that" and "which" modifiers, with some meaning stuff thrown in.

The uses of "that" and "which" can get nastier, though. Check out last Monday's YouTube webinar for more on the various uses of "that" on the GMAT... and we'll feature the other examples from the webinar as QOTDs later this week.

Quote:

A. which, causing plant and animal extinctions, marks

"Which" can only modify "North America" here, and that makes no sense at all: "North America, which... marks the end of the geologic era"?! The placement of the "-ing" modifier doesn't seem great, either. Eliminate (A).

Quote:

B. which caused the plant and animal extinctions marking

Again, the modifier beginning with "which" is modifying "North America" again, and that makes no sense: "North America, which caused the plant and animal extinctions..." Eliminate (B).

Quote:

C. and causing plant and animal extinctions that mark

I'm OK with the use of "that" here, but the parallelism doesn't work. The parallelism marker "and" is followed by "causing plant and animal extinctions", and I can't find anything in the sentence that could possibly be parallel to "causing." (C) is gone.

Quote:

D. an event that caused plant and animal extinctions, and it marks

The last part of the underlined portion makes me hesitate: "it" could refer to "event", I guess. So "...an event that caused plant and animal extinctions, and the event marks the end of the geologic era..." That's not awful, but I really don't understand why we're starting a whole new clause there, with "event" as the subject. It makes a whole lot more sense when the end of the sentence says "... marks the end of the geologic era..." function as a modifier for "extinctions" -- and that's exactly what (E) does.

Since "it" is the subject of the second clause, you could also argue that it refers back to the subject of the first clause: "an asteroid bigger than Mount Everest." But that wouldn't really make much sense, either: the asteroid marks the end of the geologic era? Hm, not so sure about that one. But either way: even if you're OK with the pronoun, (E) does a much better job of conveying the meaning of the sentence.

Incidentally, there's another version of this answer choice in the verbal guide (any edition): "an event that caused plant and animal extinctions, which marks..." Clearly, that's wrong for a different reason: "extinctions... marks" is a clear subject-verb error.

Either way, (D) is gone.

Quote:

E. an event that caused the plant and animal extinctions that mark

(E) has two "thats", and they're both perfectly fine. The event caused the plant and animal extinctions, and the extinctions mark the end of the geologic era. Nice and clear. (E) wins.

GMATNinja - i find the use of the present tense 'mark' to be a bit bizarre; in my opinion it would make mone sense to say 'marked' instead, as the events we're talking about are clearly in the past. Does that make sense? Tks!

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28 Sep 2019, 11:05

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Quote:

Good question! If we have more than one action in a sentence, it's possible that those actions could have different tenses - it all depends on logic and context. Here, have an example:

"Tim, who once loved thrash metal but now prefers polka with just a hint of clarinet, has always had eclectic taste."
In this example, Tim "loved" one kind of music in the past, but "prefers" a different kind in the present. That's totally fine.

In the OA, it's true that the asteroid slammed into earth in the past, but the extinctions still "mark" the end of that geological era today. Put another way, if we'd used the past tense, "marked" it would suggest that those extinctions no longer mark the end of the era in question, and the timeline of events had been reevaluated. There's no reason to believe this is the case. Perhaps more importantly, the other answer choices don't give us the option of "marked," so there's no reason to use this as a decision point.

For more on verb tenses on the GMAT in general, check out this video.

I hope that helps!

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08 Oct 2019, 08:02

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I don't quite get why GMATNinja is talking about a subject / verb agreement error on this answer choice:

(D) an event that caused plant and animal extinctions, and it marks

Isn't the event the subject? "event .. marks"
I don't get the comparision "exctinctions .. marks"

"Animal extinctions" isn't that the object?

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16 Dec 2019, 21:12

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chrtpmdr

I think the confusion is that there are two different versions of this question:

Quote:

(D) an event that caused plant and animal extinctions, and it marks
(D) an event that caused plant and animal extinctions, which marks

The first one appears on this thread; the second appears in multiple editions of the verbal guide.

The first version doesn't really have a subject-verb issue at all, for the reasons you mentioned. It's only the second version that does. Here's the excerpt from my explanation above, applied only to that second version:

GMATNinja

Incidentally, there's another version of this answer choice in the verbal guide (any edition): "an event that caused plant and animal extinctions, which marks..." Clearly, that's wrong for a different reason: "extinctions... marks" is a clear subject-verb error.

In the second version, "which marks..." seems to modify the nearest noun, "extinctions." And that would be a clear subject-verb error. Sure, I suppose you could argue that the phrase "which marks..." modifies the entire preceding mess ("an event that caused plant and animal extinctions"), but at minimum, that's confusing, because "an event" is so far back in the sentence. (E) is much clearer in that version of the question.

I hope that helps at bit!

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Don't worry if you got this one wrong, people! Once you understand a few of the fundamental concepts at play here, you’ll be able to knock out questions such as this in under a minute going forward.

The first thing that should jump out at you in these answer choices is the word which. On the GMAT the correct usage of this word is quite specific yet also simple to understand. Remember “,which” ALWAYS refers to the noun or compound noun before it. No exceptions. Be very careful when this word is used without a comma!
As such, in the first two answer choices which refers to North America. Once you get the hang of how this word works you would probably check off (A) and (B) right there and then, since the meaning of the sentence would make no conceivable sense:

(A) which, causing plant and animal extinctions, marks

In this answer choice North America seemingly marks the end of an era. But how could the land itself mark the end of an era? It clearly couldn’t, so it’s out. The verb causing also poses an issue, but we’ll get to that a bit later.

(B) which caused the plant and animal extinctions marking

In this answer choice North America caused plant and animal extinctions. Nope, the asteroid did! Out again.

(C) and causing plant and animal extinctions that mark

Similar to what we saw in (A) what jumps out here to me is the word causing. You see, technical terms aside, the timeline doesn't make sense. The asteroid slammed into North America in the past — and it is still causing (in the present) the end of an era that is...itself in the past? Out again. An answer choice that may work is as follows — ,and it caused the plant and plant extinctions that mark the end of the geologic era known as the Cretaceous Period — though you could still make the argument here that “it” is ambiguous (Note that the GMAT is somewhat flexible when it comes to pronoun ambiguity, though). Timelines and verb tenses are generally important to keep note of during SC. Also keep in mind that the last part of (C) isn’t complete as it stands; it requires a subject.

(D) an event that caused plant and animal extinctions, and it marks

This is a close one. The beginning of this sentence is clear and has clarity. The event clearly refers to the asteroid slamming into North America, and the event clearly caused the plant and animal extinctions. The problem here is with the word it. You see, the event didn't mark end of the era - the extinctions did. But the extinctions are plural first off and the word it is singular. If you went through every singular noun in the entire sentence that it could possibly refer to none would make any sense in terms of overall meaning. You would need “an event that caused plant and animal extinctions, and THEY mark” to keep things grammatical. But this would just make the sentence too awkward. Sorry, people, this answer falls short.

(E) an event that caused the plant and animal extinctions that mark

Looks like we got a winner here. It starts off clearly with the word event. It uses the word caused so it makes sense time-wise and is also parallel with slammed. And it also finally and clearly attributes the extinctions as marking the end of the era. Remember that refers to the noun (or compound noun) it is directly attached.

Whew, this took more words than I thought it would. But, like I said, once you grasp the few concepts at play here, a question such as this shouldn’t take you more than a minute to solve.

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15 May 2020, 20:00

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GMATNinja

A question from our sentence correction "ask me anything" thread:

GKomoku

Hello GMAT Ninja,

OGVR-2018 Book Question: 288

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.

A. which, causing plant and animal extinctions, marks
B. which caused the plant and animal extinctions and marks
C. and causing plant and animal extinctions that mark
D. an event that caused plant and animal extinctions, which marks
E. an event that caused the plant and animal extinctions that mark

in the answer choise D, can 'which' technically modify 'an event'????

Thank you for your help,

Best regards, GKomoku

Technically, I suppose that the phrase beginning with “which” could, in theory, “reach behind” the other modifier (“that caused plant and animal distinctions”), but… why the heck would we want to write the sentence that way? It’s confusing and messy. In general, you want the modifier to be as close as possible to the thing it modifies, and in this sense, (D) isn’t ideal.

Put another way, if you think that the phrase “which marks the end of the geologic era” also modifies “an event”, then we would have two different modifiers for “an event”:

So if we’re saying that both of these modify an “event”, then they need to be parallel to each other. So something like “an event that caused plant and animal distinctions and that marks the end of the geologic era…” would be much, much clearer.

(E) avoids those problems entirely. The first modifier (“that caused the plant and animal extinctions”) is right next to the thing it modifies (“an event). So is the second modifier (“that mark the end of the geologic era” modifies “the plant and animal extinctions”). So the modifiers are much, much clearer than in (D).

I hope this helps!

Hi GMATNinja
I have a different question altogether. It's related to the non-underline part.

Quote:

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America

The non-underline part highlighted in pink. Don't you think that this one is ambiguous?
One meaning can be that 60 million years ago according to some scientists, an asteroid.... It can be 50million or 100 million years according to some other scientists.
Another meaning can be that an asteroid bigger than Mount Everest slammed into N.America according to some scientists. It's possible that some other scientists believe that maybe asteroid didn't slam the earth.

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Updated on: 21 May 2020, 03:28

Originally posted by TheUltimateWinner on 20 May 2020, 15:44.
Last edited by TheUltimateWinner on 21 May 2020, 03:28, edited 1 time in total.

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Quote:

D. an event that caused plant and animal extinctions, and it marks

GMATNinja,
Thank you sir for the nice explanation.
I have a query with your new version sentence (in the highlighted part).
In the new version you are going to say -->

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused plant and animal extinctions, which marks the end of the geologic era known as the Cretaceous Period.

^^ this sentence is wrong because of the subject verb agreement. But if I say the following will it make sense?

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused plant and animal extinctions, which mark the end of the geologic era known as the Cretaceous Period.

Also, one more query.. you said :
"it" could refer to "event"---> in choice D, 'an event that caused plant and animal extinctions' is the modifier, so we can remove this part from the original core sentence, right? So, why do we bother about 'event'? My thinking says that only 'asteroid' could be the antecedent of IT (accepting the meaning does not make sense here if we replace IT with 'asteroid'). Am i missing anything in my reasoning?

GMATNinja

Quote:

E. an event that caused the plant and animal extinctions that mark

(E) has two "thats", and they're both perfectly fine. The event caused the plant and animal extinctions, and the extinctions mark the end of the geologic era. Nice and clear. (E) wins.

Also, it seems that the extinctions don't mark the end of the geologic era, an event does, because if it is because of 'extinctions' the that should be THOSE.
Sir, am i missing anything?
Thanks__

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20 May 2020, 16:11

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Hello Experts,
MartyTargetTestPrep, GMATNinja, GMATGuruNY, AjiteshArun, MentorTutoring, EducationAisle, generis

Here the correct choice is:
Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused the plant and animal extinctions that mark the end of the geologic era known as the Cretaceous Period.

What if the version is changed a bit? Is it still ok? It is better if someone clarify this new version.
Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused the plant and animal extinctions marks the end of the geologic era known as the Cretaceous Period.
.....removed "that" from original sentence and and add "s" with the verb "mark" to make the subject verb agreement with "event".

Also, another version could be:
Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that the plant and animal became extinct marks the end of the geologic era known as the Cretaceous Period.
Are these two new versions perfectly matched with meaning?
Thanks__

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20 May 2020, 16:46

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Asad

No, Asad, neither revision would work as is. The first is closer to the mark, but the article the ahead of the adjectives plant and animal would have to be altered, and marks could use some support as well. Consider:

1) Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused massive plant and animal extinctions and marks the end of the geologic era known as the Cretaceous Period.

2) Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused massive plant and animal extinctions, marking the end of the geologic era known as the Cretaceous Period.

Your second sentence above is all twisted up, and that part between an event that and marks would need some serious work, as in, an event that, because many plants and animals went extinct, marks... Note that you have turned what were previously adjectives in plant and animal into nouns, plants and animals, which is why I underlined adjectives above.

This may be a fun exercise for supplementary study, but keep in mind that a key point to improving your SC performance is to understand that you can only work with what is presented on the screen. Of the many variations of the sentence that could appear, these are the five you have to work with. Which flaws can you expose in four of the five options?

Anyway, I hope that helps. Good luck with your studies.

- Andrew

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21 May 2020, 05:36

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Asad

MentorTutoring

1) Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused massive plant and animal extinctions and marks the end of the geologic era known as the Cretaceous Period.

^^in this example, and is the parallel marker. So, what are you making parallel with 'marks'? Are you making parallel 'marks' with 'caused'?
If yes, i need to share something here...
"an event marks the end...." ---> independent clause
but,
"an event THAT caused massive ....." ---> a modifier. So, how an independent clause is paralleled with a modifier?

MentorTutoring

2) Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused massive plant and animal extinctions, marking the end of the geologic era known as the Cretaceous Period.

^^ Here in this, "marking the end......." is the direct result of previous thought (the thought should be independent!). But, in your 2nd example, "marking the end......." is the direct result of modifier, which does not have its own independent thought because that part starts with THAT (i.e., an event THAT caused...). Is the sentence that you made legit?

Quote:

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.

(A) which, causing plant and animal extinctions, marks
(B) which caused the plant and animal extinctions marking
(C) and causing plant and animal extinctions that mark
(D) an event that caused plant and animal extinctions, and it marks
(E) an event that caused the plant and animal extinctions that mark

The correct choice is E here.
In this correct choice, 'mark' is a plural verb, right? So, we need plural subject, which could be 'extinctions'. But, if 'extinctions' is the subject of 'mark' then we need to replace the THAT with THOSE because 'extinctions' is plural. On the other side, if we think that 'an event' is the subject of 'mark' then we need an 's' after the verb 'mark'! What do you think about my reasoning?
Thanks__

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21 May 2020, 15:11

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MentorTutoring

Above, in the phrase an event that caused, the that can carry over to a second item without appearing a second time, as in, an event that caused... and [that] marks. I am not overly fond of the sentence, but it could be written in such a way and be grammatically sound.

Asad

MentorTutoring

I would not have offered up an illegitimate sentence. You asked for a different way of expressing a similar notion to what was expressed in the original correct sentence, and that is all I have done. The modifying phrase starting with marking could refer to the extinctions, to the event, or all the back to the action of the asteroid slamming into North America. The appositive phrase could be skipped over without a problem. My advice? If you understand the correct answer, then stick to the phrasing of the correct answer. It holds up to scrutiny for a reason. You have probably heard the adage, If it ain't broke, don't fix it. Enough said.

Asad

Quote:

Yes, mark is a plural verb, but your reasoning is off in suggesting that THOSE replace THAT: the plant and animal extinctions those mark? I do not understand the proposed change. The pronoun that can be used to stand in for either a singular or plural subject.

1) The balloons that caused the accident were too great in number. CORRECT. The sentence conveys that these particular balloons, the ones that had caused the accident, were too numerous.

2) The balloons those caused the accident were too great in number. INCORRECT. Even if you rewrote the sentence to include those, you would still need a that as well: Those balloons that caused the accident were too great in number.

I hope you find these responses useful. I write them to assist you and the larger community. If you are unhappy with them or find them poorly reasoned, then feel free to omit my name the next time you have a question. No hard feelings, but perhaps some other person may write in a way that better resonates with you.

- Andrew

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21 May 2020, 16:30

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Many many thanks to cooperate in my studies..

MentorTutoring

Asad

MentorTutoring

^^ if this is the case, how do we explain the following official questions (LINK of this official question) where it carries 2 THAT...

Quote:

Australian embryologists have found evidence that suggests that the elephant is descended from an aquatic animal, and its trunk originally evolving as a kind of snorkel.

(A) that suggests that the elephant is descended from an aquatic animal, and its trunk originally evolving
(B) that has suggested the elephant descended from an aquatic animal, its trunk originally evolving
(C) suggesting that the elephant had descended from an aquatic animal with its trunk originally evolved
(D) to suggest that the elephant had descended from an aquatic animal and its trunk originally evolved
(E) to suggest that the elephant is descended from an aquatic animal and that its trunk originally evolved

Here E is the correct choice. If we can easily carry over that why GMAC used 2 THAT here? I'm a bit confused here..

It is better if you help the community on it.
So, can we remove one THAT from the correct version?
Australian embryologists have found evidence to suggest that the elephant is descended from an aquatic animal and ~~that~~ its trunk originally evolved as a kind of snorkel.

MentorTutoring

Asad

MentorTutoring

So far i know, 'adverbial modifier can't modify just a noun; it modifies whole thought! If there is no COMMA before VERBing then it'll surely modify the previous word (i.e., extinctions marking-->'marking' modifies 'extinctions').
If i miss anything, it is better if you help me.
Thank you...

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It appears as though I myself should have listened to the old adage mentioned earlier. I was aiming to show two ways in which a similar sentence could be written, but would they appear as such on the GMAT™ as correct answers? No. That is why GMAC™ wrote the original correct answer exactly as it appears above. On this issue of omitting that, GMAC™ is quite conservative about maintaining parallelism, and that is all that matters when it comes to preparing for the GMAT™. As for the -ing modifier, I would refer you to this response by Mike McGarry from a forum dedicated to the topic.

I apologize for the confusion. Happy studies.

- Andrew

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23 May 2020, 08:15

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harsh8686

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A question from our sentence correction "ask me anything" thread:

GKomoku

Hi GMATNinja
I have a different question altogether. It's related to the non-underline part.

Quote:

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America

You have a point: what exactly the other scientists are thinking is open to some interpretation. But the part that isn't up for debate is that "some scientists" believe that, sixty-five million years ago, an asteroid bigger than Mount Everest slammed into North America.

Whether "other" scientists disagree with all or just some of that (and to what extent they disagree) isn't entirely clear. But luckily we have the same uncertainty in all five answer choices, so I wouldn't lose much sleep over this point. There are plenty of other errors to focus on.

I hope that helps a bit!

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24 May 2020, 12:13

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GMATNinja

Quote:

A. which, causing plant and animal extinctions, marks

Quote:

B. which caused the plant and animal extinctions marking

Again, the modifier beginning with "which" is modifying "North America" again, and that makes no sense: "North America, which caused the plant and animal extinctions..." Eliminate (B).

Quote:

C. and causing plant and animal extinctions that mark

Quote:

D. an event that caused plant and animal extinctions, and it marks

Quote:

E. an event that caused the plant and animal extinctions that mark

(E) has two "thats", and they're both perfectly fine. The event caused the plant and animal extinctions, and the extinctions mark the end of the geologic era. Nice and clear. (E) wins.

GMATNinja why is the usage of present tense correct in the correct answer choice? Shouldn't "mark" be "marked" instead?

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31 May 2020, 11:51

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akshaygundeti

GMATNinja

Quote:

A. which, causing plant and animal extinctions, marks

Quote:

B. which caused the plant and animal extinctions marking

Again, the modifier beginning with "which" is modifying "North America" again, and that makes no sense: "North America, which caused the plant and animal extinctions..." Eliminate (B).

Quote:

C. and causing plant and animal extinctions that mark

Quote:

D. an event that caused plant and animal extinctions, and it marks

Quote:

E. an event that caused the plant and animal extinctions that mark

(E) has two "thats", and they're both perfectly fine. The event caused the plant and animal extinctions, and the extinctions mark the end of the geologic era. Nice and clear. (E) wins.

GMATNinja why is the usage of present tense correct in the correct answer choice? Shouldn't "mark" be "marked" instead?

"The geologic era known as the Cretaceous Period" is a definition/concept that people came up with many, many years AFTER the events actually happened. Even though the events happened in the past, those events are currently used to mark the end of the geologic era known as the Cretaceous Period.

Scientists might change their minds in the future and use (a) different event(s) to mark that end of that era. But, for now (present tense), the events referenced in this question mark the end of that era.

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22 Jul 2020, 15:25

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Hi honorable experts,
VeritasPrepHailey, AnthonyRitz
In the correct choice E, 'the event' definitely happened in the first. So, how do we use simple present (marks) for that event? Shouldn't it be better if we use simple past (marked)?
I'm not questioning the official answer, but i have a vast curiosity to know that.
Thanks...

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22 Jul 2020, 15:44

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TheUltimateWinner

Quote:

Indeed, the event happened in the past, and it caused the plant and animal extinctions in the past. However, those extinctions not only in the past marked the end of the Cretaceous Period but also continue in the present to mark the end of that period. In fact, those extinctions will always and forever mark the end of that period. Thus it is perfectly acceptable to use the present tense in this case. This is the "universal present," which is often stylistically preferred when describing something that was, is, and always will be true.

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24 Jul 2020, 12:07

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AnthonyRitz

TheUltimateWinner

Quote:

Thank you so much AnthonyRitz with +1. It helps me!
One more query:
Is there any chance to put the following 2 versions (by GMAC) at a time in options (out of 5 option)?

1/ Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused the plant and animal extinctions that mark the end of the geologic era known as the Cretaceous Period.

2/ Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, an event that caused the plant and animal extinctions that marked the end of the geologic era known as the Cretaceous Period.