According to scientists who monitored its path, an expanding cloud

Hello Everyone!

Let's tackle this question, one issue at a time, to find the correct choice! Before we dive in, here is the original question with any major differences between the options highlighted in orange:

According to scientists who monitored its path, an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking out a communications satellite.

(A) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking
(B) an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field that surrounds Earth, and it brightened the Northern Lights and also possibly knocked
(C) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, brightening the Northern Lights and possibly knocking
(D) a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brightened the Northern Lights and it possibly knocked
(E) a large storm in the magnetic field surrounding Earth was recently triggered by an expanding cloud of energized particles, brightening the Northern Lights and it possibly knocked

After a quick glance over the options, there are 2 main things we can focus on:

1. Modifiers (Are the scientists monitoring the cloud or the storm?)
2. Parallelism (brightened/brightening & knocked/knocking)

Let's start with #1 on our list: modifiers! We have to ask ourselves a couple questions to determine what order the modifiers should be in:

WHAT were the scientists monitoring?
and
WHAT brightened the Northern Lights and possibly knocked out a communications satellite?

We can tell by reading the sentence carefully that the scientists were monitoring THE CLOUD. This means the modifier "According to scientists who monitored its path" needs to come directly before the storm, which is what it's referring to! Let's see which options handle this correctly, and rule out those that don't:

(A) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking

(B) an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field that surrounds Earth, and it brightened the Northern Lights and also possibly knocked

(C) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, brightening the Northern Lights and possibly knocking

(D) a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brightened the Northern Lights and it possibly knocked

(E) a large storm in the magnetic field surrounding Earth was recently triggered by an expanding cloud of energized particles, brightening the Northern Lights and it possibly knocked

We can rule out options D & E because they don't put the modifier next to what it's modifying.

Now that we're left with only 3 options, let's move on to #2 on our list: parallelism. There are two things that happened as a result of the large storm in Earth's magnetic field: the Northern Lights were brighter, and it possibly knocked out a communications satellite. These two need to be written using parallel structure! Let's see which ones do, and rule out those that don't:

(A) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking --> NOT PARALLEL

(B) an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field that surrounds Earth, and it brightened the Northern Lights and also possibly knocked --> NOT PARALLEL

(C) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, brightening the Northern Lights and possibly knocking --> PARALLEL

There you go - option C is the correct choice! It places the modifier next to what it's modifying, and it uses parallel structure for both effects at the end!


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

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended core meaning of this sentence is that an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, and as a result, brightened the Northern Lights and possibly knocked out a communications satellite.

Concepts tested here: Meaning + Verb Forms + Modifiers + Parallelism + Grammatical Construction + Awkwardness/Redundancy

• Any elements linked by a conjunction ("and also" in this sentence) must be parallel.
• "who/whose/whom/which/where", when preceded by a comma, refer to the noun just before the comma.
• In a “phrase + comma + noun” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.
• The introduction of present participle ("verb+ing"- “brightening” and "knocking" in this case) after comma generally leads to a cause-effect relationship.
• Semicolons and the “comma + conjunction” construction are used to link two independent clauses; commas are used to link an independent clause with a dependent one; comma cannot be used to join two independent clauses.
• Information vital to the core meaning of the sentence must not be placed between two commas.

A: This answer choice incorrectly modifies "the magnetic field that surrounds Earth" with "which brightened the Northern Lights", incorrectly implying that the magnetic field brightened the Northern Lights and possibly knocked out a communications satellite; the intended meaning is that an expanding cloud of energized particles ejected from the Sun brightened the Northern Lights and possibly knocked out a communications satellite; please remember, "who/whose/whom/which/where", when preceded by a comma, refer to the noun just before the comma. Further, Option A fails to maintain parallelism between "brightened the Northern Lights" and "possibly knocking out a communications satellite"; please remember, any elements linked by a conjunction ("and also" in this sentence) must be parallel. Additionally, Option A redundantly uses "also" alongside "and", rendering it awkward and needlessly wordy.

B: This answer choice alters the meaning of the sentence through the phrase "and it brightened the Northern Lights and also possibly knocked"; the construction of this phrase incorrectly implies that the cloud of particles triggered a large storm in the magnetic field that surrounds Earth, and as a separate action, brightened the Northern Lights and possibly knocked out a communications satellite; the intended meaning is that the cloud of particles triggered a large storm in the magnetic field that surrounds Earth, and as a result,, brightened the Northern Lights and possibly knocked out a communications satellite. Further, Option B uses the needlessly wordy phrase "was what recently triggered", leading to awkwardness and redundancy.

C: Correct. This answer choice correctly uses "According to scientists who monitored its path" to modify "an expanding cloud of energized particles", conveying the intended meaning - that scientists monitored the cloud of energized particles. Moreover, Option C uses the phrase "brightening the Northern Lights and possibly knocking", conveying the intended meaning - that the cloud of particles triggered a large storm in the magnetic field that surrounds Earth, and as a result,, brightened the Northern Lights and possibly knocked out a communications satellite; please remember, the introduction of present participle ("verb+ing"- “brightening” and "knocking" in this case) after comma generally leads to a cause-effect relationship. Further, Option C avoids the grammatical construction errors seen in Options D and E, as it places no information between commas and correctly uses a comma to join the independent clause "an expanding cloud of energized particles...Earth" to the dependent clause "brightening the Northern Lights...satellite". Additionally, Option C maintains parallelism between "brightening the Northern Lights" and "possibly knocking out a communications satellite". Besides, Option C is free of any awkwardness or redundancy.

D: This answer choice incorrectly uses "According to scientists who monitored its path" to modify "a large storm in the magnetic field that surrounds Earth", incorrectly implying that the scientists monitored the storm; the intended meaning is that the scientists monitored the cloud of energized particles; please remember, in a “phrase + comma + noun” construction, the phrase must correctly modify the noun. Further, Option D incorrectly places information vital to the core meaning of the sentence - that the storm was triggered by the cloud of particles - between two commas; please remember, information vital to the core meaning of the sentence must not be placed between two commas. Additionally, Option D incorrectly uses conjunction ("and" in this sentence) to join the independent conjunctions "a large storm in the magnetic field that surrounds Earth...brightened the Northern Lights" and "it possibly knocked out a communications satellite"; please remember, semicolons and the “comma + conjunction” construction are used to link two independent clauses; commas are used to link an independent clause with a dependent one; comma cannot be used to join two independent clauses.

E: This answer choice incorrectly uses "According to scientists who monitored its path" to modify "a large storm in the magnetic field that surrounds Earth", incorrectly implying that the scientists monitored the storm; the intended meaning is that the scientists monitored the cloud of energized particles; please remember, in a “phrase + comma + noun” construction, the phrase must correctly modify the noun. Further, Option E incorrectly uses conjunction ("and" in this sentence) to join the independent conjunctions "a large storm in the magnetic field that surrounds Earth...brightening the Northern Lights" and "it possibly knocked out a communications satellite"; please remember, semicolons and the “comma + conjunction” construction are used to link two independent clauses; commas are used to link an independent clause with a dependent one; comma cannot be used to join two independent clauses.

Hence, C is the best answer choice.

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



To understand the concept of "Phrase Comma Subject" and "Subject Comma Phrase" on GMAT, you may want to watch the following video (~2 minutes):



To understand the concept of "Extra Information Between Two Commas" on GMAT, you may want to watch the following video (~1 minute):



All the best!
Experts' Global Team

Check out the video discussing this question here: https://youtu.be/5JWjr6qQAfY

What does the sentence say? That scientists were monitoring the path of either an expanding cloud or a large storm. The large storm was triggered by the expanding cloud. This triggering of the storm brightened the Northern Lights and knocked out a satellite (or we could say that the storm brightened the Northern Lights and knocked out a satellite).

We are not very clear on what the sentence is telling us. Let's look at the options.

The sentence starts with a modifier (prepositional phrase) which has a pronoun 'its.' - "According to scientists who monitored its path"
The referent of the pronoun 'its' should appear immediately after the modifier, likely as the subject of the main clause. The options show that 'its' could refer to 'an expanding cloud' or 'a large storm.' - Either works.

(A) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking

‘which’ seems to refer to the previous clause ‘the cloud … triggered a large storm…’
This is not a good GMAT practice. ‘which’ should ideally refer to a noun/noun phrase/pronoun.
‘and also’ is redundant. ‘and’ is enough.
The event led to two outcomes – ‘brightened the Lights’ and ‘knocked out a satellite.’ The events should be in parallel. ‘brightened …’ is not parallel to ‘knocking out …’
Incorrect.

(B) an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field that surrounds Earth, and it brightened the Northern Lights and also possibly knocked

‘a cloud was what triggered a large storm’ is an indirect way of saying ‘a cloud triggered a large storm.’ There is no good reason to use this.
‘it’ doesn’t have a clear referent. Did the cloud, the storm or the event brighten the Northern Lights and knock out a satellite – we can’t say. Likely the storm or the event led to the effects but the subject of the previous clause (‘cloud’ was what triggered a large storm) is ‘cloud’ and since ‘it’ is the subject of the subsequent clause, they don’t match. Hence pronoun becomes ambiguous.
(For details, check Pronoun Ambiguity Section of the module)
Incorrect.

(C) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, brightening the Northern Lights and possibly knocking

Now this looks great! It tells us that the cloud triggered the storm and this event led to two effects using ‘comma + present participle’ for both – brightening the Northern Lights and knocking out a satellite. It makes sense that the two are effects of a cause.
(For details, check Present Participles in Verbal Section of the module)
Colloquially, we can say that the storm brightened the Northern Lights etc. and it wouldn’t be wrong but the phrasing with present participle is better. These are the effects of the cloud triggering the storm. The storm didn’t knowingly brighten the Northern Lights etc.
Correct.

(D) a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brightened the Northern Lights and it possibly knocked

The issue here is the use of ‘it.’ We do not repeat the subject when the subject is the same for both clauses.
Removing all modifiers, the basic sentence structure here is:
… a large storm … brightened the Northern Lights and it possibly knocked out a satellite
‘it’ refers to the large storm and both clauses have the same subject ‘a large storm.’ We don’t need to repeat it.
Also, as discussed in option (C) above, use of ‘the storm brightened the Northern Lights etc.’ is not wrong but it is better to give it as an effect using comma + present participle.
There is no other issue with this option. It gives a sentence that is decidedly different from the first three options but there is no reason to assume that this is not what the author wanted to say. Since we have an option that makes perfect sense, we eliminate this one.
Incorrect.

(E) a large storm in the magnetic field surrounding Earth was recently triggered by an expanding cloud of energized particles, brightening the Northern Lights and it possibly knocked

In addition to the ‘it’ issue discussed in option (D) above, this option does not make sense.
‘According to scientists who monitored its path, a large storm … was recently triggered by an expanding cloud…’
What were the scientists monitoring? It seems that they were monitoring ‘a large storm.’ But the large storm was recently triggered by an expanding cloud. So how come they were watching it? They must have been monitoring the cloud instead. That is how they must have noticed that the cloud recently triggered a large storm. So this option does not make sense.
Note that this issue does not arise in option (D) because ‘recently triggered by an expanding cloud’ is a modifier of ‘a large storm.’ So it is an ‘aside’ information. The large storm could have been triggered a week ago and scientists could have been monitoring it.
But in option (E), the sentence is written to give us this information (that the cloud triggered the storm) in the main clause. Giving us this information was the main intent of the sentence so it must have been very recent. Hence it doesn’t make sense. In addition, we prefer active voice over passive voice when feasible.
Incorrect.

Answer (C)

Hi sonalchhajed2019,

There are a few issues with Answer B that ultimately make it incorrect.

1) All of the answer choices use the word "recently" - and when we're considering events that happened in the recent past, we have to ask if each event is a one-time event or something that was ongoing (and might still be happening right now). If we're dealing with an ongoing past event, then a gerund (re: an "-ing" verb) is what we should typically use in the sentence. The act of 'brightening the Northern Lights" doesn't sound like a one-time moment (re: the lights didn't quickly get really bright and then go back to normal brightness), so the gerund is likely the correct option (relative to using a simple past tense verb).

2) Since there were two results (one involving the Northern Lights AND one involving the satellite), we now have to consider Parallelism. Since we used a gerund ("brightening....") we need another gerund for the 2nd part of the Parallelism ("and... knocking").

3) Answer B also includes some other issues. First, since we already know what caused the effects in the past (re: "the expanding gas cloud... triggered") the phrase "was what" is redundant. There's another redundant phrase there too: "and also." Furthermore, I'm not in love with the usage of the pronoun "it" (as there are two singular nouns preceding that pronoun in the sentence).

GMAT assassins aren't born, they're made,
Rich

The opening modifier should correctly modify the,following portion.
"According to scientists who monitored its path","Its" should properly refer to "an expanding cloud of energized particles ejected from the Sun".So that leaves out with choice (A),(B) and (C).

(A) has -ism problem at the end of the sentence between "brightened" and "knocking"
(B) "it brightened the Northern Lights" It does not have proper antecedent.
(C)Proper -ism rule maintained

The problem is the ambiguous pronoun -It-, with many suitors. The key is to get rid of it. As per that, we can safely eliminate B, D. and E. Between A and C, it wouldn’t take much to say no to A for the very blatant touch - rule error, leaving C with good //ism and without pronoun hitch.

According to scientists who monitored its path, an expanding cloud of energized particles ejected from the Sun recently triggered a large strom in the magnetic field that surrounds Earth, which brigthened the Northern Lights and also possibly knocking out a communications satellite

A. an expanding cloud of energized particles ejected from the Sun recently triggered a large strom in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking
--> NONPARALLEL

B.an expanding cloud of energized particles ejected from the Sun was what recently triggered a large strom in the magnetic field that surrounds Earth, and it the brigthened the Northern Lights and also possibly knocked
-->illogical sentence

C.an expanding cloud of energized particles ejected from the Sun recently triggered a large strom in the magnetic field that surrounds Earth, brightening the Northern Lights and also possibly knocking
--> CORRECT

D. a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brigthened the Northern Lights and it possibly knocked
--> nonparallel/passive

E. a large storm in the magnetic field that surrounds Earth was recently triggered by an expanding cloud of energized particles, brigthening the Northern Lights and it possibly knocked
--> passive+not parallel

will go with C

Again people have knocked off B for IT- is ambiguous , I m sry but i don't agree... (it is is parallel and correctly pointing to sub of previous IC)

B) an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field
that surrounds Earth, and it brightened the Northern Lights and also possibly knocked

When We say IC, and IC -> that means both are independent....

I was shocked to see my GF with stranger in the restaurant ,and I fainted on my dinning table.

This means I was not fainted because I saw them...the reason might be something else...

In B we are providing a result so 'comma+ and' is wrong

In C we are providing V-ing which provides the result of first clause ...So C correct

I did not understand why the modifier "According to scientists who monitored its path," should modify the cloud of ...... The scientist can monitor the path of storm too right? As they do for storms on earth! Am I missing anything here? Please help!

Hi anilisanil,

Lets tale your doubt. As per your doubt, if I understood it correctly, Storm could be the Subject of the Sentence. Right. So,lets analyze the following:

D. a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brigthened the Northern Lights and it possibly knocked

Couple of Problems Here. First "Triggered" is modifying Earth, which is clearly not the Intended Meaning. Secondly, when you have two independent clauses, it must use FANBOYS and COMMA. Comma is missing here. Hence, this option is incorrect.

E. a large storm in the magnetic field that surrounds Earth was recently triggered by an expanding cloud of energized particles, brigthening the Northern Lights and it possibly knocked
Again, Comma +Fanboys problem is still here. Moreover, this choice is PASSIVE, and is not parallel.

Even if you consider the subject to be Storm, the relevant choices still have some blatant errors. Hence, you have to go for other choices. So, if you are not able to find the subject, I would suggest you to move on to choices and see if those can be ruled out. Had the Choice E been perfectly parallel, but it is in passive voice, I would still refrain myself from marking this as Answer choice. The reason is beacuse of its Passive Nature. You already have a better answer available. Right, so why would you go for something inferior.

Regards
H

According to scientists who monitored its path ==>now whose path scientists are monitoring...
it can be expanding cloud or a large storm....so basis this split we cannot eliminate any choice.

A : an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds earth, which brightened the Northern Lights and also possibly knocking
WRONG.
--use of WHICH is wrong.....WHICH is incorrectly referring to EARTH.
--AND ALSO => Together they are redundant.

B : an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field that surrounds earth, and it brightened the Northern Lights and also possibly knocked
WRONG.
--AND ALSO => Together they are redundant.
--WHAT RECENTLY=>making sentence unnecessary wordy.
--use of CLAUSE it brightened the northern lights ==> meaning = expanding cloud brightened the northern lights...BUT this is not the intended meaning.....incorrect.

C : an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds earth, brightening the Northern Lights and possibly knocking
CORRECT.

D : a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brightened the Northern Lights and it possibly knocked
WRONG.
----brightened and it possibly knocked are not parallel.
----use of IT is redundant.

E : a large storm in the magnetic field surrounding Earth was recently triggered by an expanding cloud of energized particles, brightening the Northern Lights and it possibly knocked
WRONG.
--USE OF IT is wrong .
--brightening and it possibly knocked are not parallel.

hence C

When facing tough question such as this, the easier method will be to fall back on small grammar snippets to eliminate as many wrong choices as possible first; In this case, we can eliminate A and E because, we can see the mismatch of parallelism easily; second we can eliminate B because it uses ‘and also’, a redundant expression. This leaves us with C and D; At a higher level of parallelism, we should avoid the use of the subject or its pronoun in the second arm, if it happens to be same as the subject of first arm; using “it" is said to be redundant in such cases. If the pronoun’s reference is in doubt, then that choice is fit to be dropped. We can eliminate D, and end up with C as the correct choice. This may not be a panacea for situations, but at least a handy tool

According to scientists who monitored its path, an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth. which brightened the Northern Lights and also possibly knocking out a communications satellite.

(A) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking

(B) an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field that surrounds Earth, and it brightened the Northern Lights and also possibly knocked

(C) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, brightening the Northern Lights and possibly knocking

(D) a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brightened the Northern Lights and it possibly knocked

(E) a large storm in the magnetic field surrounding Earth was recently triggered by an expanding cloud of energized particles, brightening the Northern Lights and it possibly knocked

Hello Jagwant01,

I am not sure if your doubt still persists. Here is the explanation nonetheless.

In Choice C, both brightening... and knocking... are modifiers that are placed after a clause and are preceded by a comma. Hence, they are comma + verb-ing modifiers that modify the action in the preceding clause.

Per the context of the sentence, brightening... and knocking... correctly modify the preceding action triggered. The sentence intends to say that an expanding clause triggered a large storm. This action led to two events. It brightened the Northern Lights and probably knocked out a communication satellite.

Now, the verb-ing modifiers that are not preceded by a comma act as noun modifiers and modify the preceding noun.


Hope this helps.
Thanks.
Shraddha

(A) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, which brightened the Northern Lights and also possibly knocking

(B) an expanding cloud of energized particles ejected from the Sun was what recently triggered a large storm in the magnetic field that surrounds Earth, and it brightened the Northern Lights and also possibly knocked

(C) an expanding cloud of energized particles ejected from the Sun recently triggered a large storm in the magnetic field that surrounds Earth, brightening the Northern Lights and possibly knocking

(D) a large storm in the magnetic field that surrounds Earth, recently triggered by an expanding cloud of energized particles, brightened the Northern Lights and it possibly knocked

(E) a large storm in the magnetic field surrounding Earth was recently triggered by an expanding cloud of energized particles, brightening the Northern Lights and it possibly knocked

We need the main subject " an expanding cloud" after comma. So D and E are out.

In A, "which" is wrongly modifying "Earth", and also "it" is ambiguous".

B also has modifying issues.

1. The scientists are monitoring the path (its path) of a cloud of energized particles ejected by the Sun -- The pronoun 'its' should refer to the subject of the clause namely, -the cloud-. The cloud is also the nearest noun to the pronoun.

2. As per modification rule, the modified term should be first mentioned immediately after the modifier

3. The storm is the object of the verb triggered. We can't expect a pronoun to jump over the subject to refer to the object.

Hi There,

Apologies in advance but I'm still unsure how we determined that the scientists were monitoring the cloud. I understand from the question that "an expanding cloud..." was placed after the first comma which lends itself nicely to this being the case...but is that the reason why we chose this? Furthermore, how do we determine what brightened the northern lights / possibly knocked out the satellites? If we sub in "an expanding cloud", this can make sense (i.e. it may be possible that a cloud of energized particles recently ejected from the sun brightened the northern lights and knocked out satellites)... but the storm cloud also makes sense in this case as well.

Overall just unsure. I initially picked C, then picked D and have all the regrets!

Thanks