The physical structure of the human eye enables it to sense light of

Hi Aditya,

Let me write the entire sentence taking Option D into consideration.

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible.

As you can see the pronoun “it” is ambiguous. It can refer to either “wavelength” or “infrared radiation”.

Even if you say that only wavelength can be long and so “it” properly refers to wavelength, then you can say that “thus invisible” is modifying “wavelength” in that case.

The original sentence intends to say that the “infrared radiation” is invisible to the eye because of some reasons. The original sentence doesn’t intend to say that “the wavelength is invisible”.
This is the error in Option D.

Now let us look at the entire sentence taking Option E into consideration.

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible

Again, the pronoun “it” is ambiguous. (Making radiation invisible or Making wavelength invisible?)

Also the use of “that” is incorrect.
a. Trees which give oxygen are essential for life on earth.
b. Trees that give oxygen are essential for life on earth.

Sentence (a) tells us that trees are essential for life on earth and states a property of trees i.e. Trees give oxygen.
Sentence (b) tells us that only trees that give oxygen are essential for life on earth.
This is the meaning difference between “which” and “that”

The usage of “that” in Option E brings about a similar meaning change. It is talking about “a particular wavelength of 0.1 millimeters that is too long for eye to register”, whereas the original sentence intends to say that “all wavelengths of 0.1 millimeters are too long for eye to register.”

Hope you get the difference in the meanings.
For the reasons above stated, Option E is incorrect too.

Hope this helps!

Regards,
Krishna
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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 infrared radiation is invisible because its wavelength, which is 0.1 millimeters long, is too long to be registered by the eye.

Concepts tested here: Meaning + Pronouns + Awkwardness/Redundancy

A: Correct. This answer choice correctly uses the pronoun "its" to exclusively refer to the noun "infrared radiation". Further, Option A uses the phrase "its wavelength—0.1 millimeters -"; the placement of "0.1 millimeters" between dashes conveys the intended meaning - that all wavelengths that are 0.1 millimeters long are too short for the eye to register. Additionally, Option A is free of any awkwardness or redundancy.

B: This answer choice suffers from pronoun ambiguity, as the pronoun "it" can refer to either "the wavelength of infrared radiation" or just "infrared radiation". Further, Option B uses the needlessly wordy phrase "making it invisible", leading to awkwardness and redundancy.

C: This answer choice suffers from pronoun ambiguity, as the pronoun "it" can refer to either "wavelength" or "infrared radiation".

D: This answer choice suffers from pronoun ambiguity, as the pronoun "it" can refer to either "the wavelength of infrared radiation" or just "infrared radiation". Further, Option D uses the needlessly wordy phrase "and thus invisible", leading to awkwardness and redundancy.

E: This answer choice suffers from pronoun ambiguity, as the pronoun "it" can refer to either "wavelength" or "infrared radiation". Further, Option E alters the meaning of the sentence through the phrase "wavelength of 0.1 millimeters that is too long"; the use of "that" incorrectly implies that there is a specific wavelength that is 0.1 millimeters long and too short for the eye to register; the intended meaning is that all wavelengths that are 0.1 millimeters long are too short for the eye to register. Additionally, Option E uses the needlessly wordy phrase "thus making it invisible", leading to awkwardness and redundancy.

Hence, A is the best answer choice.

All the best!
Experts' Global Team
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Hi! This question is an excellent test of modification, which is heavily tested on the GMAT.

As always, when first evaluating a sentence it's best to ignore the "extra bits" - focus on the subject and verb.

First, we recognize that the semicolon divides two equal sentences; in effect, we can ignore everything that comes before it. So, let's only focus on the underlined portion.

In the original (and, of course, choice (A)), we have:



Seems like a perfectly sound sentence - it's clear what's invisible (IR), "its" has a single clear antecedent (IR) and no style issues. Lookin' good!

Next up is (B):


This one isn't as clear: "it" is supposed to refer to IR, but actually modifies the subject of the sentence, "the wavelength". As noted by our Trojan-loving poster, a prepositional phrase can't be the subject, so even though (B) contains "of infrared radiation" that's not a legal parent noun for "it".

Here's another very useful general rule for the GMAT: ignore prepositional phrases. Such phrases appear all the time and are pretty much always just in there to distract you from the basic sentence structure.

Next we have (C):


More pronoun problems (pronouns are another very commonly tested grammar concept)! "it" at the end of the sentence could refer to either IR or wavelength. When you see an ambiguous pronoun, move on!

(Technically pronouns refer to the closest "legal" preceding parent noun - in this sentence that would be "wavelength" - but for the most part the GMAT abhors pronoun ambiguity.)

How about (D):


Same issue as (B) - "of infrared radiation" can't be the antecedent for "it".

Finally (E):


"that" renders this sentence awkward; also, "it" at the end could refer to IR, wavelength or the eye.

C, D and E: it's not clear what the "it" is referring to.
B: "making it invisible" is misplaced and modifies "eye" changing the meaning.
A: is clear and grammatically correct.

I chose A as well

(A) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye --> Correct
(B) however, the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible "it" does not refer to a clear antecedent
(C) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it "it" does not refer to a clear antecedent
(D) however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible "because" is awkwardly placed with "however"
(E) however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible "it" does not refer to a clear antecedent

Everything about choice C

I don't agree with the notion that "it do not refer to a clear antecedent" or "it refers to wavelength"

Reason:In choice C, we already got a "its", so "it" and "its" must refer to the same subject---infrared radiation.

So, what is wrong with choice C?

IMO, "it" is redundant here.
the sentence"because its wavelength···is too long for the eye to register" is complete, and we do not need a "it" after register!

Hi nson.

You're correct. "it" is redundant in C.
For example:
WRONG: The test took me 1 hour to complete it <== "it" is redundant.
CORRECT: The test took me 1 hour to complete

Same question:
rivaling-the-pyramids-of-egypt-or-even-the-ancient-cities-of-30856.html?fl=similar

Hope it helps.

In option C, “it” actually does not have a clear antecedent and therefore, option C has a pronoun ambiguity error.
Let’s look at option C:

Infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it.

Here is the sentence structure of Option C:
1. Infrared radiation, however, is invisible
2. because its wavelength—0.1 millimeters—is too long for the eye to register it

A: Now, if we look at it, the beginning of the second clause has possessive pronoun “its” – this pronoun clearly refers to Infrared radiation since there is no other noun before this pronoun.

B: However, when we reach the end of the second clause and encounter “it”, we have two nouns to which “it” could refer to – “Infrared radiation” or the subject of the “because clause” i.e. wavelength. Now, both the nouns are valid contenders for the antecedent of “it”. Therefore, there is a pronoun ambiguity in the clause.

For this reason, option C is incorrect.

Does this help!

Chiranjeev
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Please explain how reference to it in choice D and E is wrong. IN D,E og says reference to it is not clear. can you highlight this.. is it in these sentences pointing wavelength or infrared (both) ?? how it in B is clear? Is the same error not in B ?

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye.

Analyses of the sentence:

The Physical Structure ..... enables IT(eye- clear antecedent) to sense light of....; Infrared radiation..... is invisible because ITS wavelength- .........

Although the first IT is in non-underlined portion , we will analyse all pronoun-antecedent pairs.

We will run the MGMAT Sc guide proposed filtering test to check for pronoun ambiguity.

(1). Number / Gender:

First IT can refer to EYE(singular) and structure(singular) [Number]
Second ITS can refer to "Infrared radiation","light", "eye", and "structure".

(2). Repeats : Second ITS can refer to EYE as the FIRST one refers to EYE.

(3). Proximity: FIRST IT is closer to EYE, so refers to EYE
SECOND ITS is closer to "IR", so refers to IR

(4). Case: There is no point of case as IT is in same clause.
We don't have || clauses here so cannot apply this step.


(A) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye
Correct as is and as explained above.
(B) however, the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible
Making what invisible - "the wavelength" or the IR
(C) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it
We apply repeats , proximity and case.
Repeats => IT logically refers to IR
Proximity => IT refers to EYE
Case => No || clauses

(D) however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible
EYE is thus INVISIBLE - nonsense
(E) however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible
Repeats => IT occurs only once
Proximity => IT refers to EYE
Case => IT appears to refer to IR correctly
But "THAT" clauses restricts the 0.1 MM wavelength=> change in meaning

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye.
(A) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye - Correct
(B) however, the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible - Verb- ing making illogically modifies making
(C) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it - Pronoun it does not have clear antecedent
(D) however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible - Verb invisible does not make sense
(E) however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible - Illogical contrast

Answer A
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Hello AjiteshArun GMATNinja VeritasKarishma

Could you please explain in option e the logical antecedent for 'it' should be Infrared Rays as wavelength couldn't be invisible as it is a property of a wave to have wavelength we are correct to say wave disappeared not wavelength. I only felt option e made most sense.

Thanks,
Ankush

Posted from my mobile device

Isn't "to be" in (A) seems to refer to something which is yet to happen?

Is the pronoun ambiguity too much in Option (C) to reject it? There are many GMAT questions where even if pronoun "it" has not antecedent or if there is little bit ambiguity, it still becomes the right answer. So, apart from pronoun ambiguity, is there any other reason to reject C?

I was differentiating b/w "too long to be registered" vs "too long for the eye to register it", where latter sounded better.

The logical antecedent of 'it' is infrared rays since wavelength or eye cannot be made invisible. Anyway, pronoun ambiguity is not a big issue.

(E) is incorrect because of the use of 'that' after .1 mm. 'that' modifies the noun immediately before it i.e. '.1 mm'. It should actually modify 'wavelength'.
'IR has a wavelength that is too long for the eye to register...' is correct.
It tells us what kind of wavelength IR has.
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In a way, yes! The eye is not capable of registering the wavelength of infrared radiation. So it certainly makes sense that the eye has NOT yet registered the wavelength of infrared radiation.

This is a common construction. For example:

• "The child is too short to ride the roller coaster." - The child has not yet ridden the roller coaster.
• "Tim is too busy to be a part-time model." - Tim has not yet become a part-time model.

Great observation! The GMAT isn't very consistent when it comes to pronoun ambiguity, so it's best to look for other decision points.

In choice (C), we definitely have some pronoun ambiguity. The first "it" clearly refers to "infrared radiation." But the second "it" could refer to either "infrared radiation" OR "wavelength." (A) avoids that issue altogether. Also, as you noted, (A) is a bit better idiomatically.

Is (C) wrong? Maybe not. But (A) is a better choice.

I hope that helps!
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Request Expert Reply:
What does IT play role in choice C? If IT refers to 'wavelength' then IT makes the sentence redundant, but if IT refers back to both 'wavelength' and 'infrared radiation' then it resembles me as pronoun ambiguity? So, what's the perfect explanation for the use of IT in choice C? It is 'redundant' or 'pronoun ambiguity'?
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Hi TheUltimateWinner

Let us plug in option (C) into the original sentence:

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it.

The final word, "it" cannot refer to both wavelength and infrared radiation, since "it" is a singular pronoun and hence must only refer to a singular noun. In this sentence, it could refer to either one of these, and hence the antecedent is not clear. That is the reason for eliminating option (C).

Hope this clarifies.
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Literal meaning: infrared radiation is invisible because its wavelength is too long to be registered by the eye.
Looks good. No error. Good to keep for now


Literal meaning: wavelength of infrared radiation is too long to be registered by the eye making wavelength invisible.
Doesn't make sense, since wavelength is not supposed to be visible. Rather, radiation is. Reject (B)


Literal meaning looks good, but we are not sure of what 'it' refers to. 'it' could refer to wavelength, which would make it incorrect, or 'it' could refer to infrared radiation, which would be fine. But that ambiguity makes (C) a less preferred option over (A). Reject it


Same error as is in (B). Reject (D)


same issue with 'it' as in (C). Option looks good to shortlist, but (A) is much clearer. Thus, reject (E)

Correct answer is (A)
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Hello ,

I understand that the first INDEPENDENT Clause has been separated by 2nd clause with the semicolon. However, still these two clauses are related, so by ignoring the first clause aren't we ignoring the fact that contrast is intended to be brought about in this SC. So If we keep ''however'' within the punctuation, aren't we making it non-essential (Since now it can be removed). How will it then serve creating the intended contrast.

Or is it that we should completely ignore the 1st clause as a matter of fact in all such question types?

Please assist.