Recently documented examples of neurogenesis, the production of new br

The first thing to notice here is that we are looking for examples of neurogenesis. Because neurogenesis is an activity, a kind of growth, neither mice nor their brains can be an example of neurogenesis. We can eliminate A - C for this reason. We can eliminate D because it has a modifier error. "When placed" is an adverbial modifier, and should therefore modify an action or clause. For instance, we might say "When placed in a stimulating environment, mice grow new brain cells," or "Mice grow new brain cells when placed in a stimulating environment." All we have to modify here is a noun phrase--"the brain growth"--so we should not use an adverbial modifier. Note that we have the same modifier in A, but it is wrong for a slightly different reason. There, we have "the brain growing," which can be interpreted as an action, but now when we apply "when placed in a stimulating environment," it looks like we are saying that [i]the brain,[i] rather than the mouse, is being placed in that environment.

Note that in E, we have a noun modifier--"that are placed in a stimulating environment." This correctly modifies "mice." In turn, the phrase "in mice" correctly modifies "brain growth" to provide an example of neurogenesis. The parallel portion about canaries works in exactly the same way.
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Almost everyone is going with 4. From my poin of view that is wrong. Here is how....

the brain growth in mice when placed (what is placed mice or brain growth) a stimulating environment or the increase in canaries' neurons when they (what does THEY refer to here. They is a pronoun that should refer to a noun, in this case the noun is canaries' neurons. Remember canaries' is in possessive form here).

5 resolves it all.

mice is a plural of mouse(singular).

brain growth in mice that are placed in a stimulating environment
or an increase in neurons in canaries that learn new songs.

I may be wrong because my brain is disfunctional these days....

OA is E!

Interesting that nobody got it right My answer was B when I first saw this SC.

This is what happens (according to me): it parallels examples of the production of new brain cells, i.e. nouns or noun phrases. However, the trick is the modifiers following these noun/noun phrases. The modifiers are either subordinate clauses or relative clauses. One should read the options with the modifying clauses in mind and correct accordingly.

A. the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that

- the modifying clauses are not parallel.

B. mice whose brains grow when they are placed in a stimulating environment or canaries whose neurons increase when they

- incorrect use of mice and canaries as examples (examples need to be of the production of new brain cells). Also, ambiguous use of they

C. mice’s brain that grow when they are placed in a stimulating environment or canaries’ neurons that increase when they

- incorrect use of mice's brain and canaries' neurons as examples. Also, ambiguous use of they in the second example

D. the brain growth in mice when placed in a stimulating environment or the increase in canaries’ neurons when they

- the examples are not parallel (canaries' neurons is in possessive form whereas the brain growth is not). Also, the modifying clauses are ambigious. E.g., they in the second example

E. brain grown in mice that are placed in a stimulating environment or increase in neurons in canaries that

- the examples and the modifying clauses are parallel.


Let me know if anyone is of a different opinion...

Recently documented examples of neurogenesis, the production of new brain cells, include the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that learn new songs.

A. the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that

Seems like the 'brain' is being disembodied and placed in a stimulating environment.

B. mice whose brains grow when they are placed in a stimulating environment or canaries whose neurons increase when they

The 'they' is ambiguous in both cases: it could refer to 'brains' or 'mice', and in the second case it could refer to 'neurons' or 'canaries.'

C. mice's brains that grow when they are placed in a stimulating environment or canaries' neurons that increase when they

Same pronoun ambiguity with 'they.'

D. the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they

Sounds as if the 'brain growth' is placed in a stimulating environment.

E. brain growth in mice that are placed in a stimulating environment or an increase in neurons in canaries that

The pronoun ambiguity issue is cleared up here: 'that' clearly refers to 'mice' and the second 'that' refers to canaries. Therefore (E) is the answer.
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Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of the crucial part of this sentence is that brain growth in mice that are placed in a stimulating environment and an increase in neurons in canaries that learn new songs are examples of the action, neurogenesis.

Concepts tested here: Meaning + Modifiers

• "when" is only used to refer to a point in time.

A: This answer choice alters the meaning of the sentence through the phrase "the brain growing in mice"; the construction of this phrase illogically implies that the brains of the mice placed in a stimulating environment is an example of neurogenesis; the intended meaning is that the growth of the brains of mice that are placed in a stimulating environment is an example of neurogenesis. Further, Option A incorrectly uses "when" to refer to "mice"; please remember, "when" is only used to refer to a point in time.

B: This answer choice alters the meaning of the sentence through the phrases "mice whose brains grow" and "canaries whose neurons increase"; the construction of these phrases illogically suggests those mice whose brains grow when the mice are placed in stimulating environments and those canaries whose neurons increase when the canaries learn new songs are examples of neurogenesis; the intended meaning is that the growth of the brains of mice that are placed in a stimulating environment and the increase in neurons of canaries that learn new songs are examples of neurogenesis.

C: This answer choice alters the meaning of the sentence through the phrases "mice's brains that grow" and "canaries' neurons that increase"; the construction of these phrases illogically suggests the brains of the mice placed in a stimulating environment and the neurons of canaries that learn new songs are examples of neurogenesis; the intended meaning is that the growth of the brains of mice that are placed in a stimulating environment and the increase in neurons of canaries that learn new songs are examples of neurogenesis.

D: This answer choice incorrectly uses "when" to refer to "mice" and "canaries"; please remember, "when" is only used to refer to a point in time.

E: Correct. This answer choice uses the phrases "brain growth in mice" and "an increase in neurons in canaries", conveying the intended meaning - that the growth of the brains of mice that are placed in a stimulating environment and the increase in neurons of canaries that learn new songs are examples of neurogenesis. Further, Option E avoids the modifier error seen in Options A and D, as it does not use the word "when".

Hence, E is the best answer choice.

All the best!
Experts' Global Team
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Here the answer is E. Let me show you how.

This is a split sentence. Basically in the form of [main sentence, description, main sentence]

Just take out the description in the middle and read it like this:

Recently documented examples of neurogenesis include [A] or .

From this alone, you should be able to eliminate (A), (B), and (C) just be reading the first three words of each answer choice.

(A): the brain growing
(B): mice whose brains
(C): mice's brains

None of these work because they are not structured correctly as examples.

[b](D) and (E) are closer to what we want--either "the brain growth" or "brain growth"

The only difference between (D) and (E) is "when placed" versus "that."
"When placed" seems to suggest a more specific condition whereas "that" seems more general and a description of a state of being--more of what we're looking for.

Also, if you were to guess--choose the shorter answer choice--the one with fewer words---that would be (E).

Either way, the one you want here is (E) because it correctly begins with "brain growth in mice"--which is an example of a documented example of neurogenesis. And it's consistent with the second part of the sentence.

Therefore, the answer is (E).

Hi there,

Recently documented examples of neurogenesis, the production of new brain cells, include the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that learn new songs.

Here is the difference between choice D and choice E:

Choice D: the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they: According to this choice, “brain growth” is placed in a stimulating environment. This is illogical because it is the mice that are put in such environment. Again, pronoun “they” refers to “neurons”, meaning that neurons learn new songs. This is illogical. Note that pronoun “they” cannot refer to “canaries’” because it is an adjective an not a noun. For these reasons choice D is incorrect.

Choice E. brain growth in mice that are placed in a stimulating environment or an increase in neurons in canaries that: Correct. In this choice, the first “that” correctly refers to “mice” and the second “that” to “canaries”.

Hope this helps.
Thanks.
Shraddha
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I would pick (E).

Recently documented examples of neurogenesis, the production of new brain cells, include the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that learn new songs.

A. the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that - brain growing in mice is awkward - wrong
B. mice whose brains grow when they are placed in a stimulating environment or canaries whose neurons increase when they - they seems to be refering to brains and neurons - wrong
C. mice's brains that grow when they are placed in a stimulating environment or canaries' neurons that increase when they - they seems to be refering to mice's brains and canaries' neurons - wrong
D. the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they - they refering to canaries' neurons - wrong
E. brain growth in mice that are placed in a stimulating environment or an increase in neurons in canaries that - correct - mice are placed in stimulating and canaries that learn new songs - clear

No, a wrong answer cannot be eliminated because of use of "when".

Option D is eliminated not because "when" is used, but because parallelism is lost.

In option D, "when placed in a stimulating environment" comprises of a participle ("placed"), whereas "when they learn new songs" comprises of a clause. D would be better if the last part were as follows: "when learning new songs" (participle instead of clause.)

Moreover "increase in Neurons IN CANARIES" in E (rather than "increase in canaries' neurons)" in D goes better with "brain growth IN MICE"

Another problem with D is that the subject pronoun "they" refers to the possessive antecedent "canaries' "

Here's the version created via the use of (D).

Recently documented examples of neurogenesis, the production of new brain cells, include the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they learn new songs.

This part all makes sense: Recently documented examples of neurogenesis, the production of new brain cells, include the brain growth in mice

Here's the first spot in which it goes wrong: the brain growth in mice when placed in a stimulating environment

Notice that what that basically says is this: the brain growth in mice when placed in a stimulating environment

It doesn't say what is placed in a stimulating environment. Something is placed in a stimulating environment, but that can't be brain growth, because the brain growth happens when something else is "placed in a stimulating environment."

Also, the sentence does not say that the mice are placed in a stimulating environment. So, this version leaves out a key thing, what exactly is placed in a stimulating environment.

Furthermore, "when placed in a stimulating environment" has to modify a verb. Something happens "when," such as "when placed in a stimulating environment, mice experience brain growth," or "the brain growth seen in mice when they are placed in a stimulating environment," but no verb is present for "when placed in a stimulating environment" to modify.

The next issue is here: the increases in canaries' neurons

What exactly is an increase in canaries' neurons? The sentence does not say "increases in the number of neurons" or "increases in the sizes of neurons." It does not even say what (E) says, "an an increase in neurons in canaries," which is certainly not ideal but at least makes some sense. It says simply "increases in canaries' neurons,'" as if the neurons themselves somehow experience increases.

Objects can't increase. For example, this does not make sense. "After the rain, we observed increases in the tree's apples." The were increases in the apples themselves? Doesn't make sense.

So, "increases in canaries' neurons" doesn't make sense either.

The use of "they" is not ideal but not terrible. We can tell that the neurons don't learn new songs. So, "they" must refer to "canaries." The fact that "canaries''' is in the possessive form is not a clear flaw, at least in GMAT SC terms, because there are SC questions in which the correct answer includes a pronoun that refers to a noun in the possessive form. That said, the fact that "they" somehow seems to refer to "neurons" does add to the case for finding a choice better than this one.
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A. Incorrect - the brain growing in mice when placed in a stimulating environment
B. Incorrect - they can refer to canaries or neurons
C. Incorrect - canaries' neurons that increase when they learn new songs
D. Incorrect - neurons when they learn new songs
E. Correct

Recently documented examples of neurogenesis, the production of new brain cells, include the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that learn new songs.

A. the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that
B. mice whose brains grow when they are placed in a stimulating environment or canaries whose neurons increase when they
C. mice's brains that grow when they are placed in a stimulating environment or canaries' neurons that increase when they
D. the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they
E. brain growth in mice that are placed in a stimulating environment or an increase in neurons in canaries that

The pronoun 'they is indeed a serious problem and one of the most eligible points for an easy POE. 'They' might refer to the examples, which is the subject of the whole sentence or the plural mice, or the brain cells etc in the first part. The same 'they' strangely may refer to the canaries or the neurons in the second part.

With so much muddle, it will be best to avoid any choice containing 'they' such as B, C, and D on the D-day. Now it will be easy to discard A since the choice talks of the brain rather than the brain's growth. This leaves us with the freedom to choose E.

But the jarring note is that the choice refers to examples. but still, uses the conjunction 'or' rather than 'and'.
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miko2010

There's nothing inherently wrong with using a WHEN modifier in this context. A-C all use "when" correctly to narrow down the situation in which growth occurs. D uses "when" incorrectly, as I outlined in a previous post. (relevant portion pasted below)

We can eliminate D because it has a modifier error. "When placed" is an adverbial modifier, and should therefore modify an action or clause. For instance, we might say "When placed in a stimulating environment, mice grow new brain cells," or "Mice grow new brain cells when placed in a stimulating environment." All we have to modify here is a noun phrase--"the brain growth"--so we should not use an adverbial modifier.
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IMO -That refers to things

in option E 'that' refers to mice & canaries

So can 'that' refers to living creatures and things except People?

Also in option B we have ambiguity in pronouns - the first "they" would automatically be "brains", and the second would automatically be "neurons"

I feel option E also has same case as in B - the first "that" would automatically be "mice", and the second 'that' automatically be "Canaries"

Please advise where my reasoning going wrong

"when" is replace time not replace place. so we can eliminate A,B,C and D

Hi Jay, when looking for parallelism, we should not look at word on word similarity; for example, in option E, the presence of an in one phrase does not necessitate the presence of an in the other phrase.

The structure of option E is:

...include brain growth in mice ...or an increase in neurons...

Both the bold parts are Noun-phrases, and hence parallel.
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There's no clause after "when." If there were, as in, "when they are placed," the structure would be a clause.

A "trigger" is only good as a "flag." It doesn't tell the whole story.
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Notice that "when placed in a stimulating environment" is not a clause. It's a phrase. So, as I discussed above, it's an adverbial phrase with nothing to modify.


The issue is that the sentence does not convey that the mice were placed in that environment. We know that the growth is not placed there, but the sentence does not say what is placed there.


As I discussed above, "they" would not logically refer to "neurons" because neurons do not "learn new songs."

So, the use of "they" is not clearly incorrect, and the issues I outlined above are the best reasons for eliminating (D).
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jabhatta2

"When" normally works as an adverbial modifier. As you stated in your follow-up, we can use "when" to modify time periods-- "The year when I visited Singapore"--but this is the exception, not the rule. There is simply no way for a phrase such as "when placed in a stimulating environment" to work as a noun modifier. What would it mean? That phrase can only describe what a noun (e.g. animal) does in a certain situation. That's an adverbial modifier.
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