The displays can heat the atmosphere to do two things. 1. to affect the trajectories blah, blah and 2. ( to) induce electric currents blah blah . So an – and - is required between - missiles - induce - to complete the series with proper parallelism.


E is the correct answer.
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in A you have run-on sentence, (comma splice).
Use and to join two independent clauses.
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E
[enough to..] and [the northern lights heat and induce]
A implies that the missile induce[s] no

+1 E

"enough to" is the idiom. B, C, and D out.
There are two effects of these northern lights: affecting the trajectories of ballistic missiles AND inducing electric currents. AND is needed. E is the answer.
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I chose A

I assumed "can heat the atmosphere over the arctic enough to affect the trajectories of ballistic missiles" to be a modifier modifying Aurora lights. Why is this wrong? So I read the question as "Displays of the aurora borealis, BLAH BLAH BLAH (modifier) , induce electric currents that can cause blackouts in some areas and corrosion in north-south pipelines.

So 'Displays' is plural and goes with 'induce' and by virtue of which other answer choices are wrong. What did I miss?

Hi ace312, I don't think "can heat the atmosphere over the arctic enough to affect the trajectories of ballistic missiles" is modifying Aurora lights. Consider below example (I just made up),

Sunlight from sun, can heat earth's surface - here Sunlight is heating earth's surface, not sun, the same way Displays are heating atmosphere, not the aurora borealis in the below example. Hope this clears your doubt or reply if you have more questions.

If the sentence uses "inducing" after comma in option A, will it be considered right?

Damn!! GMAT is a tricky test. The point is that we should never ever underestimate the need to read and understand the sentence!
I choose A because the sentence was correct and parallel. Then when i saw the OA i realized
" induce electric currents that can cause X (blackouts in some areas) and Y (corrosion in north-south pipelines)" need and before it to make it parallel with the first part .

can heat... enough to affect in A and E is more idiomatic than the use of the subordinate clause beginning with "that" in B, C, and D.

B - produces an illogical and ungrammatical statement by making induce parallel with the verb heat rather than with the appropriate form of the verb affect;

C - lacks agreement in using the singular pronoun it to refer to the plural noun displays

D is faulty because induces cannot fit grammatically with any noun in the sentence.

A incorrectly separates the two infinitives to affect and [to] induce with a comma when it should compound them with and, as does E.

Working out on such mechanical way to think to disentagle a question is not a really efficient manner to overcome this difficult test.

As such, surely knowing the grammar rules is the cornerstone but is not the way.

Based only on meaning

Displays of the aurora borealis, or "northern lights", can heat the atmosphere over the arctic enough to affect the trajectories of ballistic missiles, induce electric currents than can cause blackouts in some areas and corrosion in north-south pipelines.

a) to affect the trajectories of ballistic missiles, induce

induce is not inducing at least and also is a sentence in which the meaning is broken: induce what ??

b) that the trajectories of ballistic missiles are affected, induce

passive: wrong and convoluted

c) that it affects the trajectories of ballistic missiles, induces

it refers to what behind itself ??

d) that the trajectories of ballistic missiles are affected and induces

same B

e) to affect the trajectories of ballistic missiles and induce

Clearly and straight. No doubt reading the sentence as it is constructed
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gmatpunjabi, You may refer the picture as attached.

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Hi,

I'm absolutely on board with the two things and how they need to be connected but I can't make peace with this bit - "to" is an infinitive of purpose. Using "to" almost seems like the displays heat the atmosphere with the intention to 1. affect the trajectories ... 2. ( to) induce electric currents... but that isn't the intended meaning right. The meaning is that these two things CAN be a result of the displays.

Please help!

Best
SS18

actually, the display can generate heat that is enough to do two things (or you can say, the display can generate enough heat that can cause two things) viz. 1. to affect the trajectories...... and 2. ( to) induce electric currents.........

These two effect of that heat is presented as 1. to affect the trajectories...... and 2. ( to) induce electric currents......... and they need to be in parallel form

Can someone from egmat or Magoosh mikemcgarry help with my query below?

[/quote]

Hi ss18

Although I know you have asked specific experts to respond your query, I hope you will allow me to help you with it.

You are right, that "+to infinitive" is used to indicate intentions. So, the following sentence would fall under this usage:

I went to her place to collect my parcel. - I went there with the intention to achieve something.

However, that's NOT the only use of "+to infinitive". The "+to infinitive" can be used in many other ways too. For instance, one way is to use it after adverbs.

I was tired enough to fall asleep as soon as I hit the bed. - This means that I was so tired that I fell asleep as soon as I hit the bed; it does not mean that I became tired with the intention fall asleep.

This is the exact same usage that you find in the correct sentence as well. You can read more about the general use of "+to infinitive" at http://www.ef.com/english-resources/english-grammar/infinitive/. However, I would not recommend going overboard in your research. Also, not all usages maybe tested on the GMAT.

Cheers!

As per the meaning of the sentence affect should be parallel to induce. Only option E does this correctly and precisely.

So here the display of the aurora borealis has 2 affects- 1. it would heat the atmosphere and 2. It would induce the electric current in some areas. So these two affects need to be connected by the conjunction " and ". apart from the meaning error , Is there any other error committed in the original sentence. Please correct me if my understanding is wrong. Thank you

Displays of the aurora borealis, or "northern lights", can heat the atmosphere over the arctic enough to:
affect the trajectories of ballistic missiles
AND
induce electric currents that can cause:
blackouts in some areas
and corrosion in north-south pipelines.


A.to affect the trajectories of ballistic missiles, induce
B. that the trajectories of ballistic missiles are affected, induce
C. that it affects the trajectories of ballistic missiles are affected and induces
D.that the trajectories of ballistic missiles are affected and induces
E. to affect the trajectories of ballistic missiles and induce

Here's the official explanation provided by the GMAC for this question:

This sentence describes two effects of the aurora borealis. It heats the atmosphere enough to affect x and (to) induce y; the preposition to does not need to be repeated because it is understood. The conjunction and is necessary to show that the two effects are equal and separate. When they are separated only by a comma, the second effect appears to be part of the first one, which is not true.

Option A: To affect and (to understood) induce should be joined by the conjunction and rather than separated by a comma

Option B: The correct idiom is can heat… enough to affect; that violates the idiom and introduces an illogical sequence of verbs (are affected, induce)

Option C: The correct idiom is can heat… enough to affect; that violates the idiom; the verbs should be joined by a conjunction rather than separated by a comma

Option D: That violates the correct idiom can heat… enough to affect; the verbs illogically change tenses

Option E: Correct. In this sentence, the two effects are shown to be equal and separate in a grammatical construction that correctly joins to affect and (to understood) induce.

The correct answer is E.

Please note that I'm not the author of this explanation. I'm just posting it here since I believe it can help the community.
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