Sentence Correction

what it/they refer to in this sentence correction question.

92. 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

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

First, notice that answer choices C, D, and E all have the construction "freshwater snails which." This is incorrect. "Which" is non-restrictive, so when it follows immediately after a noun, it will be preceded by a comma. "freshwater snails, which..." "That" is restrictive and does not follow a comma. A and B use the restrictive "that" correctly.

So now we have to choose between "part of its life cycle" and "part of their life cycle." The relevant clause here is: "irrigation projects have
enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle." The intended meaning: "irrigation projects have
enlarged the habitat of the freshwater snails that are the parasite's hosts for part of the parasite's life cycle. Because the possessive pronoun "its" refers to "the parasite's", we prefer the singular "its."

Answer is A

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.

GMATGuruNY 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.

Dear Mitch,

How come there same pronoun 'it' with different antecedents? In the non underline sentence 'it' refer to the 'worm' and the 'its' refer to 'parasite's'. Is not it violation for a rule that we can 't have two antecedents for one pronoun?

Thanks

Mo2men wrote:Dear Mitch,

How come there same pronoun 'it' with different antecedents? In the non underline sentence 'it' refer to the 'worm' and the 'its' refer to 'parasite's'. Is not it violation for a rule that we can 't have two antecedents for one pronoun?

Thanks

Generally:
Within a SINGLE CLAUSE, forms of the same pronoun should have the same antecedent.
OA: 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.
Here, it (which serves to refer to schistosomiasis) is contained within the main clause in red, while its (which serves to refer to parasite's) is contained within the subordinate clause in blue.
Since they are contained within different clauses, the two usages are correct.