The brain is something of a stimulus reduction system, a means to redu

yes, stimulus is in fact a countable noun.

what got me thinking about amount was the word infinite but is should be
number of stimuli

Harshgmat , this sentence is well-written and very complicated in grammar lingo. I can understand why you are curious about it!

I have never seen punctuation this sophisticated tested by GMAC in ANY OG question.*

The commas before and after "in order to comprehend" are needed to indicate that we are shifting for a moment to insert a SEMI-parenthetical explanation.

A true "parenthetical aside": Professor Melnyk, of course, laughed at the student's funny comment.
A true aside in the middle of an expression is always set off by two commas and can be removed from the sentence without altering its meaning.

The phrase "in order to comprehend" is a bit more than a parenthetical aside. Removing the phrase changes the meaning. But the phrase does interrupt.

Let's try the sentence without the commas.

The brain is something of a stimulus reduction system, a means to reduce in order to comprehend the nearly infinite number of stimuli that reach the senses at any given moment.

To reduce WHAT? Without a comma, we have no indication that "in order to comprehend" is an interruption (is a shift in THOUGHT and LOGIC). At that point, "to reduce" looks as if it has no direct object or a very elusive one.

Without a boatload of jargon and a sentence diagram, the best way to explain all the commas is this: if there is a distinct shift in the sentence, thought process, or logic, use a comma.

The phrase "in order to comprehend" and its commas indicate that we are interrupting the flow of the sentence to explain why the brain must first reduce the nearly infinite number of stimuli.

So we need a comma before and after "in order to comprehend":

1) to signal that the preceding verb "to reduce" is connected to the direct object "number," which immediately follows "comprehend"; and

2) to indicate that we are interrupting a verb phrase to explain WHY the brain needs to reduce the number of stimuli. That's a shift in thought.

Finally, the commas clarify meaning. The sentence is a bit unorthodox. Good prose often is unorthodox.

Are you confused by the meaning of the sentence?

Below is a very ugly version of the meaning of this sentence. Words in brackets indicate exactly that which the commas suggest without saying a word. I would rather read the sentence in the prompt (with the correct option B inserted).

MEANING:
The brain is [a type of] a stimulus reduction system.
[In other words, the brain is] a means to reduce the nearly infinite number of stimuli that reach the senses at any given moment.
[The brain functions as a means to reduce the number of stimuli] in order to comprehend [a then-manageable number of] the stimuli.

If I were to explain all the modifiers in this sentence, I would be writing for days.

The question doesn't test modifiers. It tests

-- countability: Stimuli can be counted. We can have an infinite NUMBER of stimuli.
Eliminate A, D, E

(C) the means of reducing for comprehending
--idiom: THE as a definite article in (C) ruins an otherwise idiomatic construction.

-- verbs: the verbs in this option make no sense. "Reducing" is a TRANSITIVE verb in participle form that needs an object. (Reducing WHAT?) "For comprehending" is not an object.
Eliminate C

Answer B

*Just to clear any concern that you or others may have -- punctuation this intricate would not be tested.

It's B right? I attacked it from the other end. guess stimuli is countable.

Hi, can a moderator add underline? It was a bit tough to understand the question without it.

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GMATT73, between A and B, how did you determine that stimuli is countable? Or is this just common knowledge?

Stimuli can be broken down, categorized, labeled, and archived = countable.

Hi, can a moderator add underline? It was a bit tough to understand the question without it.

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Done that, thanks for pointing out KUDOS added.

The brain is something of a stimulus reduction system, a means to reduce, in order to comprehend, the nearly infinite amount of stimuli that reach the senses at any given moment.

I have a question here...

Why comma is required between
...comprehend,the nearly....

Can someone explain modifiers in the sentence and what is it modifying?

a)a means to reduce
b)the nearly infinite amount of stimuli that reach the senses at any given moment

daagh GMATNinja generis

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generis

Thanks for very detailed and eloborate reply.

This will surely be very helpful to other members also.

Keep it up!!

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you are the man!! brilliant explanation!

Though I knew that stimuli is countable what made me choose option A is the word "infinte". How can we count infinite things ? There are infinite integers but it doesn't mean that we can count and list all of them. The meaning of the word "infinite" itself means "not countable".

Experts please help. I think this is highly debatable. Magoosh GMATNinja generis Abhi077 GMATNinjatwo ManhattanPrep

You make it sound very straightforward. I suspect this is quite debatable.

Stimulus can be both countable and uncountable. In a case like this one, I would prefer to treat stimulus as uncountable. The number of stimuli referred to here, that the brain meets, is so vast that it becomes an uncountable amount.

I vote for A. At least I would have written that way.

https://www.wordreference.com/definition/stimulus

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You may, for example, have an infinite number of prime numbers. But I agree with you that this is far from decided. You can also have an infinite amount of prime numbers, because when something is no longer countable, there is no practical meaning left in the countability of a noun. And language is not a strictly grammatical system, but also highly semantical.

However, If we get some proof that GMAC are very strict with countability rules, there is a point for us to stick to that rule in the context of this test. I doubt though that GMAC would use a debatable example like this one as a decisive point on a real question.

Bottom line: Im not an expert.

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Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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