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Schistosomiasis, a disease caused by a parasitic worm

by sahilchaudhary » Tue Oct 22, 2013 8:11 am
Schistosomiasis, a disease caused by a parasitic worm, is prevalent in hot, humid climates, and it has become more widespread as irrigation projects have enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle.

(A) the freshwater snails that are the parasite's hosts for part of its life cycle
(B) the freshwater snails that are the parasite's hosts in part of their life cycle
(C) freshwater snails which become the parasite's hosts for part of its life cycles
(D) freshwater snails which become the hosts of the parasite during the parasite's life cycles
(E) parasite's hosts, freshwater snails which become their hosts during their life cycles

OA will be posted later.
I have read the explanations provided for this question on this site, but not satisfied with that.
Expert help is deeply appreciated.
Sahil Chaudhary
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by theCodeToGMAT » Tue Oct 22, 2013 8:54 am
{A} - CORRECT
{B} - INCORRECT; "their"
{C} - INCORRECT; "that" is preferred as per the requirement..
{D} - INCORRECT; "that" is preferred as per the requirement..
{E} - INCORRECT; "their"

Is it [spoiler]{A}[/spoiler]?
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by Mike@Magoosh » Tue Oct 22, 2013 12:18 pm
sahilchaudhary wrote:Schistosomiasis, a disease caused by a parasitic worm, is prevalent in hot, humid climates, and it has become more widespread as irrigation projects have enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle.

(A) the freshwater snails that are the parasite's hosts for part of its life cycle
(B) the freshwater snails that are the parasite's hosts in part of their life cycle
(C) freshwater snails which become the parasite's hosts for part of its life cycles
(D) freshwater snails which become the hosts of the parasite during the parasite's life cycles
(E) parasite's hosts, freshwater snails which become their hosts during their life cycles

OA will be posted later.
I have read the explanations provided for this question on this site, but not satisfied with that.
Expert help is deeply appreciated.
Dear sahilchaudhary,

I'm happy to help. :-) This is question # 92 from the Verbal Review - 2nd Edition of the Official Guide - Sentence Correction (page 310).

Split #1: restrictive vs. non-restrictive clauses. See:
https://magoosh.com/gmat/2012/that-vs-which-on-the-gmat/
The modifier following snails is not set off by a comma, so it must be a restrictive modifier, and for the GMAT, we must use "that", not "which". Choice (C) & (D) & (E) make this mistake.

Split #2: the pronoun before "life cycle" seems to refer to the "parasitic worm", not the "freshwater snail." It's true, the word "parasite" appears in the possessive, so it would not be a proper antecedent for a pronoun, but earlier in the sentence, "a parasitic worm" is mentioned. That's singular, so the pronoun must be singular. Choice (A) & (C) get this correct. For more on pronouns, see:
https://magoosh.com/gmat/2013/gmat-pronoun-traps/

It would seem the answer is [spoiler](A)[/spoiler], which is what they list as the OA.

Could one argue that maybe they are talking about the snail's life cycle, not the worm's life cycle? Perhaps. It seems to me that the question does not provide conclusive evidence that we should choose the latter over the former. Perhaps choice (D) is meant to communicate this, but it would be highly unusually for a crucial ambiguity to be resolved only in one of the answer choices, a choice other than (A). I suspect this question would not pass the vetting process to make it all the way to the real GMAT. For an official question, this contains a rare instance of ambiguity affecting answer choice.

Does all this make sense?

Mike :-)
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by sahilchaudhary » Tue Oct 22, 2013 12:52 pm
theCodeToGMAT wrote:{A} - CORRECT
{B} - INCORRECT; "their"
{C} - INCORRECT; "that" is preferred as per the requirement..
{D} - INCORRECT; "that" is preferred as per the requirement..
{E} - INCORRECT; "their"

Is it [spoiler]{A}[/spoiler]?
Yes the correct answer is A.
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by sahilchaudhary » Tue Oct 22, 2013 12:54 pm
Mike@Magoosh wrote:Dear sahilchaudhary,

I'm happy to help. :-) This is question # 92 from the Verbal Review - 2nd Edition of the Official Guide - Sentence Correction (page 310).

Split #1: restrictive vs. non-restrictive clauses. See:
https://magoosh.com/gmat/2012/that-vs-which-on-the-gmat/
The modifier following snails is not set off by a comma, so it must be a restrictive modifier, and for the GMAT, we must use "that", not "which". Choice (C) & (D) & (E) make this mistake.

Split #2: the pronoun before "life cycle" seems to refer to the "parasitic worm", not the "freshwater snail." It's true, the word "parasite" appears in the possessive, so it would not be a proper antecedent for a pronoun, but earlier in the sentence, "a parasitic worm" is mentioned. That's singular, so the pronoun must be singular. Choice (A) & (C) get this correct. For more on pronouns, see:
https://magoosh.com/gmat/2013/gmat-pronoun-traps/

It would seem the answer is [spoiler](A)[/spoiler], which is what they list as the OA.

Could one argue that maybe they are talking about the snail's life cycle, not the worm's life cycle? Perhaps. It seems to me that the question does not provide conclusive evidence that we should choose the latter over the former. Perhaps choice (D) is meant to communicate this, but it would be highly unusually for a crucial ambiguity to be resolved only in one of the answer choices, a choice other than (A). I suspect this question would not pass the vetting process to make it all the way to the real GMAT. For an official question, this contains a rare instance of ambiguity affecting answer choice.

Does all this make sense?

Mike :-)
Thanks for the excellent explanation. I have 2 questions.

1. As far as what I have read is that usually essential modifiers use that (without comma) and non essential modifiers use which (with comma). Is it correct ?

2. As you said the modifier is restrictive, we must use that. Is this always the case ?
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by GMATGuruNY » Tue Oct 22, 2013 1:19 pm
sahilchaudhary wrote:Schistosomiasis, a disease caused by a parasitic worm, is prevalent in hot, humid climates, and it has become more widespread as irrigation projects have enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle.

(A) the freshwater snails that are the parasite's hosts for part of its life cycle
(B) the freshwater snails that are the parasite's hosts in part of their life cycle
(C) freshwater snails which become the parasite's hosts for part of its life cycles
(D) freshwater snails which become the hosts of the parasite during the parasite's life cycles
(E) parasite's hosts, freshwater snails which become their hosts during their life cycles
I received a PM requesting that I comment.

In B and E, their (plural) cannot serve to refer to the worm (singular).
Eliminate B and E.

A life cycle is defined as the series of stages through which a living thing passes during the course of its life.
A living thing cannot have more than one life cycle.
Incorrect: a tiger's life cycles
Correct: a tiger's LIFE CYCLE
Thus, in C and D, life cycles (plural) does not convey the intended meaning.
Eliminate C and D.

The correct answer is A.
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by Resp007 » Wed Oct 30, 2013 1:03 pm
yes, from the options, except D, it seems the last pronoun "its/their" is referring to Snail's life cycle rather than the parasite's life cycle !

:)
Mike@Magoosh wrote:
sahilchaudhary wrote:Schistosomiasis, a disease caused by a parasitic worm, is prevalent in hot, humid climates, and it has become more widespread as irrigation projects have enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle.

(A) the freshwater snails that are the parasite's hosts for part of its life cycle
(B) the freshwater snails that are the parasite's hosts in part of their life cycle
(C) freshwater snails which become the parasite's hosts for part of its life cycles
(D) freshwater snails which become the hosts of the parasite during the parasite's life cycles
(E) parasite's hosts, freshwater snails which become their hosts during their life cycles

OA will be posted later.
I have read the explanations provided for this question on this site, but not satisfied with that.
Expert help is deeply appreciated.
Dear sahilchaudhary,

I'm happy to help. :-) This is question # 92 from the Verbal Review - 2nd Edition of the Official Guide - Sentence Correction (page 310).

Split #1: restrictive vs. non-restrictive clauses. See:
https://magoosh.com/gmat/2012/that-vs-which-on-the-gmat/
The modifier following snails is not set off by a comma, so it must be a restrictive modifier, and for the GMAT, we must use "that", not "which". Choice (C) & (D) & (E) make this mistake.

Split #2: the pronoun before "life cycle" seems to refer to the "parasitic worm", not the "freshwater snail." It's true, the word "parasite" appears in the possessive, so it would not be a proper antecedent for a pronoun, but earlier in the sentence, "a parasitic worm" is mentioned. That's singular, so the pronoun must be singular. Choice (A) & (C) get this correct. For more on pronouns, see:
https://magoosh.com/gmat/2013/gmat-pronoun-traps/

It would seem the answer is [spoiler](A)[/spoiler], which is what they list as the OA.

Could one argue that maybe they are talking about the snail's life cycle, not the worm's life cycle? Perhaps. It seems to me that the question does not provide conclusive evidence that we should choose the latter over the former. Perhaps choice (D) is meant to communicate this, but it would be highly unusually for a crucial ambiguity to be resolved only in one of the answer choices, a choice other than (A). I suspect this question would not pass the vetting process to make it all the way to the real GMAT. For an official question, this contains a rare instance of ambiguity affecting answer choice.

Does all this make sense?

Mike :-)
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by Resp007 » Thu Oct 31, 2013 7:34 am
If any one can please comment on the split between options A and B, i.e. between "hosts for" vs "hosts in" ?
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by Mike@Magoosh » Thu Oct 31, 2013 8:57 am
Resp007 wrote:If any one can please comment on the split between options A and B, i.e. between "hosts for" vs "hosts in" ?
Dear Resp007,
I'm happy to help. :-)

That's a false split. Those two ways of saying this are both perfectly fine, and they mean the same thing.
hosts in part of their lifecycle
hosts for part of their lifecycle
Both of these denote that part of the lifecycle is the time when the snails are the hosts.

Does this make sense?
Mike :-)
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by Winner2013 » Fri Jan 31, 2014 5:35 am
Sorry to refer to an old question,but I have a query. In option A - it feels like 'its' is ambiguous. Can someone please explain how it refers to parasite because parasite is used in possessive form right before 'its'.

Thanks,
Pooja
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by GMATGuruNY » Fri Jan 31, 2014 5:48 am
Winner2013 wrote:Sorry to refer to an old question,but I have a query. In option A - it feels like 'its' is ambiguous. Can someone please explain how it refers to parasite because parasite is used in possessive form right before 'its'.

Thanks,
Pooja
Since its and parasite's are both POSSESSIVES, it is crystal clear that the referent for its (a possessive pronoun) is the preceding possessive construction (parasite's).
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by Winner2013 » Sat Feb 01, 2014 12:10 pm
Thank u Mitch :-) I understand the pronouns better now. Your explanations are always great.

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by yashvardhan90 » Sat Aug 29, 2015 9:59 am
Hi

The sentence already has an it in the non-underlined part which refers to disease, then how can it be refer to parasite further in the sentence. As the rule states a pronoun must refer to the same antecedent in the complete sentence.

Please explain
Schistosomiasis, a disease caused by a parasitic worm, is prevalent in hot, humid climates, and it has become more widespread as irrigation projects have enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle
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by Mike@Magoosh » Sat Aug 29, 2015 10:55 am
yashvardhan90 wrote:Hi

The sentence already has an it in the non-underlined part which refers to disease, then how can it be refer to parasite further in the sentence. As the rule states a pronoun must refer to the same antecedent in the complete sentence.

Please explain
Schistosomiasis, a disease caused by a parasitic worm, is prevalent in hot, humid climates, and it has become more widespread as irrigation projects have enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle
Dear yashvardhan90,

I'm happy to respond. :-) My friend, with all due respect, you are being a little too rigid with that rule. In a short sentence, or within a single independent clause, absolutely yes, the same pronoun must refer to the same thing. BUT, when we have a huge sentence with multiple independent and dependent clauses, clauses nested in side other clauses, as we have here, then the rule is relaxed: as long as the pronoun in one location of the sentence has an unambiguously clear antecedent, then the same pronoun in another part of the sentence can refer to a different unambiguous antecedent. Parallelism is also a big clue for antecedents, and this is underappreciated. For example, the first "it" is the subject of the second independent clause, so the parallelism makes it unambiguous that its antecedent have to be the subject of the first independent clause, "Schistosomiasis."

The GMAT loves throwing long sentences at us, with all kinds of nested structures, because this challenges any simple understandings of grammar. For more on nested structures, see:
https://magoosh.com/gmat/2014/nested-gra ... orrection/

Does all this make sense?
Mike :-)
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by conquistador » Tue Sep 29, 2015 4:31 am
Mike@Magoosh wrote:
Resp007 wrote:If any one can please comment on the split between options A and B, i.e. between "hosts for" vs "hosts in" ?
Dear Resp007,
I'm happy to help. :-)

That's a false split. Those two ways of saying this are both perfectly fine, and they mean the same thing.
hosts in part of their lifecycle
hosts for part of their lifecycle
Both of these denote that part of the lifecycle is the time when the snails are the hosts.
Does this make sense?
Mike :-)
I believe this is no proper split.
But for part of life-cycle makes better sense as I feel for indicates the duration of time.
but I feel in part of life-cycle is wrong not only in this sentence but also structurally.
experts comment :)
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