Molecular evidence and comparisons of the biological mechanisms that a

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Molecular evidence and comparisons of the biological mechanisms that algae use to harvest light  have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing  a photosynthesizing phylum and gained the ability to make its own food.

A) have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing

B) have convinced scientists that both red and green algae are descended from a single endosymbiotic event, in which a eukaryotic cell swallowed
 
C) have convinced scientists that both red and green algae having descended from a single endosymbiotic event, when a eukaryotic cell that swallowed

D) has convinced scientists that both red and green algae are descended from a single endosymbiotic event, wherein a eukaryotic cell swallowed

E) has convinced scientists that both red and green algae are descendants of a single endosymbiotic event, and a eukaryotic cell swallowing

generis · Answer

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rvgmat12 · Answer

SV agreement being tested.

Has v have split -
Subject is plural so eliminate D and E.

Molecular evidence and comparisons of the biological mechanisms that algae use to harvest light have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing a photosynthesizing phylum and gained the ability to make its own food.

A) have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing
With modifies the subject. Incorrect

B) have convinced scientists that both red and green algae are descended from a single endosymbiotic event, in which a eukaryotic cell swallowed
Correct

C) have convinced scientists that both red and green algae having descended from a single endosymbiotic event, when a eukaryotic cell that swallowed
When - used for time. Incorrect

D) has convinced scientists that both red and green algae are descended from a single endosymbiotic event, wherein a eukaryotic cell swallowed
Incorrect

E) has convinced scientists that both red and green algae are descendants of a single endosymbiotic event, and a eukaryotic cell swallowing
Incorrect

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harshitverma14 · Answer

In my opinion, the answer should be 'B'

There are a few concepts that are tested here:
SV Agreement
Usage of Pronoun
Parallelism

Starting with have vs has split, whenever the two nouns are connected with 'and' its always plural. so in this case DE are out since they use 'has' for 'Molecular evidence and comparisons of the biological mechanisms' which is actually a plural subject.

D) has convinced scientists that both red and green algae are descended from a single endosymbiotic event, wherein a eukaryotic cell swallowed ( incorrect)

E) has convinced scientists that both red and green algae are descendants of a single endosymbiotic event, and a eukaryotic cell swallowing ( incorrect)

Now, coming to option C, when is a time marker and should specifically be used to denote time.

C) have convinced scientists that both red and green algae having descended from a single endosymbiotic event, when a eukaryotic cell that swallowed (incorrect, wrong pronoun usage)

Now b/w A and B, there is a slight difference in the meaning, B is parallel to the non underlined part and conveys the correct meaning.

A) have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing ( Not parallel , does not convey correct meaning, incorrect )

B) have convinced scientists that both red and green algae are descended from a single endosymbiotic event, in which a eukaryotic cell swallowed (eukaryotic cell swallowed and gained the ability to make its food)
CORRECT

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zhanbo · Answer

My answer is  (B) . It took me 01:37.

This question really boils down to the choice between (A) and (B) because we can identify major issues in (C) through (E):
(C) "both red and green algae having descended" does not contain main verb and cannot be a proper subordinate clause. 
(D) and (E) can be eliminated because of SVA (Subject Verb Agreement). Subject "Molecular evidence and comparisons of the biological mechanisms" are plural.

Between (A) and (B), (B) is definitely clear and straightforward, meaning that we cannot come up with a strong reason to eliminate (B). 
(A) uses absolute phrase, which is fancier; GMAT SC does not prefer fancy construction when a straightforward option suffices. 
In order to refute (A) confidently, though, I can only hazard a guess: "with + noun + present participle" is typically used to describe an action that happens concomitantly with the action described in main clause. In (A), the main verb is "have convinced scientists". Because "a eukaryotic cell swallowing" must have occurred well before the main verb, the use of " "with + noun + present participle" is inappropriate.

RajatJ79 · Answer

Molecular evidence and comparisons of the biological mechanisms that algae use to harvest light  have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing  a photosynthesizing phylum and gained the ability to make its own food.

Pre-thinking :  Parallelism  seems to be an obvious error in the subordinate clause. 'swallowed' and 'gained' should be used.  Subject Verb Agreement  in the main clause should also be considered where a plural subject requires a plural verb ' have  convinced'

A) have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell  swallowing  
 Parallelism in subordinate clause. Correct verb should be 'swallowed'

B)   have convinced   scientists that both red and green algae are descended from a single endosymbiotic event,   in which   a eukaryotic cell   swallowed  
 SVA in the main clause is correct. Parallelism in subordinate clause is correct. 
 
C) have convinced scientists that both red and green algae  having descended from  a single endosymbiotic event , when  a eukaryotic cell that swallowed
 Incorrect usage of 'having descended from'

D)  has  convinced scientists that both red and green algae are descended from a single endosymbiotic event, wherein a eukaryotic cell swallowed
 SVA in the main clause. Singular verb used with plural subject.

E)  has  convinced scientists that both red and green algae are descendants of a single endosymbiotic event, and a eukaryotic cell swallowing

IMO Answer should be Option B.

ramlala · Answer

Molecular evidence and comparisons of the biological mechanisms that algae use to harvest light  have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing  a photosynthesizing phylum and gained the ability to make its own food.

1st split is  Molecular evidence and comparisons of the biological mechanisms  - plural subject. D & E out
Verb is missing in  C  for subject  both red and green algae 
parallelism error between  swallowing  and  gained . A is out

A) have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell  swallowing

B) have convinced scientists that both red and green algae are descended from a single endosymbiotic event, in which a eukaryotic cell swallowed
 
C) have convinced scientists that both red and green algae  having  descended from a single endosymbiotic event, when a eukaryotic cell that swallowed

D)  has  convinced scientists that both red and green algae are descended from a single endosymbiotic event, wherein a eukaryotic cell swallowed

E)  has  convinced scientists that both red and green algae are descendants of a single endosymbiotic event, and a eukaryotic cell  swallowing

IMO B

winterschool · Answer

Molecular evidence and comparisons of the biological mechanisms that algae use to harvest light have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing a photosynthesizing phylum and gained the ability to make its own food.

A) have convinced scientists that both red and green algae are descendants of a single endosymbiotic event,  with  a eukaryotic cell  swallowing   Incorrect

with uses wrong
.............swallowing .............and gained ............. - parallelism error

B)  have convinced scientists that both red and green algae are descended from a single endosymbiotic event, in which a eukaryotic cell swallowed   Incorrect

C) have convinced scientists that both red and green algae  having  descended from a single endosymbiotic event,  when a eukaryotic cell  that swallowed  Incorrect

having uses wrong
incomplete modifier - when a eukaryotic cell ?

D)  has  convinced scientists that both red and green algae are descended from a single endosymbiotic event, wherein a eukaryotic cell swallowed  Incorrect

Molecular evidence and comparisons of the biological mechanisms - plural, so has uses wrong

E)  has  convinced scientists that both red and green algae are descendants of a single endosymbiotic event, and a eukaryotic cell swallowing  Incorrect

same as D

AkashM · Answer

Eliminate A because swallowing and gained are not parallel in this case (although -ing and -ed forms can be parallel). Also a quick glance at B would tell us that it would be better if the part after the comma explains the event.

Eliminate D and E because they use 'has' rather than 'have'. 
Eliminate C because its a mess. 'Having descended' and then what? Also, usage of when suggests a ridiculous possibility.

B remains and is the correct answer.

CrackverbalGMAT · Answer

Molecular evidence and comparisons of the biological mechanisms that algae use to harvest light  have convinced scientists that both red and green algae are descendants of a single endosymbiotic event, with a eukaryotic cell swallowing  a photosynthesizing phylum and gained the ability to make its own food.

A)  have  convinced scientists that both red and green algae are descendants of a single endosymbiotic event,  with a eukaryotic cell swallowing  
The plural verb “have” is in agreement with the plural subject- Molecular evidence and comparisons of the biological mechanisms
“swallowing” is not parallel to “gained”
Eliminate

B)  have  convinced scientists that both red and green algae are descended from a single endosymbiotic event,  in which  a eukaryotic cell  swallowed 
The plural verb “have” is in agreement with the plural subject- Molecular evidence  and  comparisons of the biological mechanisms
In which correctly refers to an endosymbiotic event
“swallowed” is parallel to “gained”
 Correct .

C)  have  convinced scientists that both red and green algae  having descended  from a single endosymbiotic event,  when  a eukaryotic cell that swallowed

“having descended from a single endosymbiotic event” functions as a modifier. This makes it a sentence fragment. Incorrect. 
What is that the scientists are convinced about?
That both red and green algae are descended from a single endosymbiotic event.
“when” refers to time. It cannot be used to refer to the endosymbiotic event

D)  has  convinced scientists that both red and green algae are descended from a single endosymbiotic event,  wherein  a eukaryotic cell swallowed

The singular verb “has” is not in agreement with the plural subject “Molecular evidence and comparisons of the biological mechanisms”

E)  has  convinced scientists that both red and green algae are descendants of a single endosymbiotic event,  and a eukaryotic cell  swallowing

The use of “has” is incorrect for the same reason as D.

Vishnupriya
CrackVerbal Prep Team

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GMAT Sentence Correction (SC - EA only) Questions

Molecular evidence and comparisons of the biological mechanisms that a

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