The presence of blue-green algae blooms i

Question

The presence of blue-green algae blooms in Lake Erie has disrupted regular water supply for over 400,000 people in Ohio, their numbers  increasing to hazardous levels  as a result of polluted runoff from industries and farmlands and warm temperatures.

A) increasing to hazardous levels
B) are increasing to hazardous levels
C) were increased to hazardous levels and 
D) have increased to hazardous levels 
E) increasing to hazardous levels and
 
Sourced from RSSing.com - neither OA nor OE is available. - open to a wide discussion and consensus. The deferred OA is not the official one

Rohitbedi · Accepted Answer

Let's break the sentence in two parts: Part 1: The presence...in Ohio Part 2: Their numbers...warm temperatures.
Now the part 1 is a complete sentence on its own whereas part 2 starts with a possessive suggesting a dependent clause would come. Also comma + possessive is a dependent clause and two independent clauses must not be joined with simply a comma. Hence, any option that can make part 2 an independent clause must be eliminated (B,C, D.)

Between A and E, A is our clear choice as "and" in E makes the sentence illogical and meaningless.

Hence, A is correct

Hope it helps!!

AndrewN · Answer

Hello,  warrior1991 . (A) is the only defendable answer, since it is the one that correctly incorporates what is known as an absolute phrase, the ambiguous  their  notwithstanding. These questions give GMAT™ aspirants plenty of grief, from what I have observed on the forum. My guess is that the problem lies in the phrase itself appearing to be an aborted clause. However, an absolute phrase modifies the whole sentence and  should be  missing a main verb in the following structure:

noun ] +  participle ] +

The presence of blue-green algae blooms in Lake Erie has disrupted regular water supply for over 400,000 people in Ohio,  their numbers   increasing  to hazardous levels as a result of polluted runoff from industries and farmlands and warm temperatures.

Answer choices (B), (C), and (D) all place a verb after numbers, creating what is known as a comma splice—a grammatically  incorrect  sentence in which a comma stands in for a period or semicolon. That is, you cannot join two independent clauses with nothing more than a comma (i.e. without a conjunction). Thus, the only grammatical sentences are (A) and (E). Between the two, the latter part of (E), the  and , should make it an easy elimination.

I do not think the sentence would appear as is on the GMAT™, but you should know how to identify an absolute phrase, since, again, they pop up now and again in 700-level questions.

I hope that helps. Thank you for thinking to ask me.

- Andrew

aditya201819 · Answer

what is wrong with D here? could not understand why A was chosen over D

mailabhishekmathur · Answer

I also chose D as the correct answer but now i realized if we put D in the original sentence the whole sentence becomes a run on sentence. Both the clauses are separated only by a comma(have increased will become the verb). If we use verb+ing it modifies the sentence and doesn't form a runon sentence.

Please correct me if i m wrong

vasuca10 · Answer

sudarshan22   hazelnut   GMATNinja  sir Kindly guide why Option D is incorrect here and why Option A is correct

JS1290 · Answer

Hi,

Though I am not one of the experts that you tagged, I can still shed some light on why option D is incorrect. Option D is a full independent clause with a subject and a verb. We cannot have two independent clause joined by merely a comma as this would be classified as a run-on sentence. Option A on the other hand is an absolute phrase and is neat and succinct. Please do make a note on this as there are several OG questions out there where a trap answer is similar to option B/C/D (full clause joined only by a comma) and the correct answer is similar to option A (absolute phrase).

Hope this helps!

Doer01 · Answer

Hi,
 This is such a classic FANBOYS example. Since the second clause/modifier, "their.....temperatures", is in a non underlined portion of the sentence, we can ignore the options trying to make it an independent clause. So, B,C, & D are out. Between A & E, E uses "and", which is a parallel marker and meaning less here.

Hence, A is correct.

Shrey9 · Answer

so, we use A or E because we are describing, a situation (increase in numbers) that happened in the first clause, with the second clause here ?

Doer01 · Answer

Hi,
 I wouldn’t say describing. Its more of a consequence/event to result sequence. 
Something happens in the lake and resulted in something else.

Posted from my mobile device

MoulikaSaxena · Answer

Hi,

I found the usage of "their" here a bit ambiguous in terms of its modified entity. can someone explain how to resolve this?

Abhishek009 · Answer

Alga is the singular noun and requires a singular verb

Algae is the plural form and requires a plural verb

MoulikaSaxena · Answer

Posted from my mobile device

No I meant it seems like their is referring to presence and not algae

NikhilST · Answer

Hello

I rejected B, C, D as it was leading to a sentence running into a sentence (run-on). Between A and E, I chose A because of the wrong usage of and.

Hope my explanation helps!

warrior1991 · Answer

AndrewN

why  is D not correct ??I marked A as an answer after reading the sentence twice but now when I am reviewing it, I find it difficult to eliminate D

warrior1991 · Answer

Thank you so much. It is very helpful when you chip in quickly after I tag you. Thanks for answering to all my queries so far. I have learnt a lot from your explanations.

AndrewN · Answer

That is great to hear. I like to offer my thoughts whenever I can, and this day finds me with a little more time on my hands. (Just luck of the draw.) Still, I do aim to reply whenever I am tagged, whether the question is of higher quality, reasonable quality (like this one), or dubious quality (so that I point out what I feel is lacking in the sentence for everyone to appreciate).

Keep working through questions little by little, study what makes them tick. More and more questions will not make you better, but grasping the underpinnings of a few questions has broad application.

- Andrew

VerbalBot · Answer

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The presence of blue-green algae blooms i

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