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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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.

In C "it" is referring to infrared radiation, which is incorrect.

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

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

a)infrared radiation,however, is invisble because its wavelength-0.1millimeters-is too long to be registered by the eye.
b)however,the wavelength of infra red radiation is-0.1 millimeters-is too long to be registered by the eye making it invisible.
c)infrared radiation,however,is invisible because its wavelength-0.1 millimeters-is too long for the eye to register it.
d)however, because the wavelength of infrared radiation is 0.1 millimeters,it is too long for the eye to register and thus invisible.
e)however,infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register,thus making
it invisible.

Hi,
We can straight forward eliminate B,C and E for Ambiguous pronoun reference 'it'. D has got a wrong sentence construction. A is the answer.

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

a)infrared radiation,however, is invisble because its wavelength-0.1millimeters-is too long to be registered by the eye.
b)however,the wavelength of infra red radiation is-0.1 millimeters-is too long to be registered by the eye making it invisible.
c)infrared radiation,however,is invisible because its wavelength-0.1 millimeters-is too long for the eye to register it.
d)however, because the wavelength of infrared radiation is 0.1 millimeters,it is too long for the eye to register and thus invisible.
e)however,infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register,thus making it invisible.

Besides the IT problem, "for - to" is unidiomatic

Want to know if there is any rule which establishes that "it" in C/D/E is referring to "wavelength"?
In D, I can though say it upto some extent, but not in C/E . It has shaken some of my basics. Can some1 explain this?

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

Difficult question. thanks for all your inputs. I learned that the word "that" in option E implies a particular wavelength of certain measurement.

Split1) Logical predication. You have a semicolon just before. That means, I need to have a complete thought in the second part of the sentence. The Ideal way to create a sentence is to have the main noun at the very beginning. That’s why A and C look great with ""infrared radiation"". I do my split focusing on A and C....have not even looked at B, D, or E because that split is not preferred. Could come back to B, D, and E if A or C are out for some reason.

Split2) Now, looking at A and C. they are both pretty similar except that one has ""to be"" while the other one has ""it"". To be is an issue. I got used to GMAT not liking the verb to be in a sentence. But I also know that the pronoun ""it"" does not have a clear referent. So C is out. Why? the GMAT not liking a verb is not the only reason to get rid of A. However, ""it"" not having a clear referent is a clear reason for C to be out.

What happened with C, D, and E? in the real test I would not look for more. I would stop and have selected A as the answer. For practice, let's do the rest.

Split3) in D, ""it"" can refer to both infrared radiation or wavelength => plus you have ""thus"" which is expanding on ""it"". We dont know what ""it"" is talking about in D. In E, has a similar issue with ""it"". In E, the use of ""that"" also implies that the sentence is talking about a specific/particular type of wavelength of some measurement, when in fact we need to talk about all the wavelengths that have the same measurement. As for B. ""it"" does not have a clear referent similar issue with C. "

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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1. We have semicolon in the first part of sentence (not underlined), it means that the second part of the sentense has to be independent one ------> it means, that it can not start from "however".
"However" continues the first part, and it is not the case here -------> B, D, E are out.

2. Between A and C. Yes, C has an active voice, but there is no need in "it" in the end - it isredundant - we already have wavelength.

A

sometimes we see that two nouns are in place of the subject of the verb. we have to decide which noun as subject is more logic.
specifically, wavelenth or infrared radiation should be invisible. I think radiation should be invisible. this decison totally depend on our common sense of this world and is not related to grammar. dont panic when we see this case.

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: 'its wavelength' clearly refers to 'infrared radiation'.

(B) however, the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible Incorrect: the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible. 'it' refers to 'the wavelength' - doesn't make sense.

(C) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it Incorrect: 'its' refers correctly to 'infrared radiation'. Unfortunately the last word, 'it', incorrectly refers to either 'wavelength' or 'eye'.

(D) however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible Incorrect: 'and thus invisible' needs an 'is' to be correct. In any case, 'it' refers to the wavelength and not infrared radiation, making the same error as (B).

(E) however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible Incorrect: 'that' is modifying wavelength so doesn't really make sense. 'making' also modifies the closest noun, which is 'eye'.

I rejected option E because i found "thus and making" redundant. Both are doing the same work- showing result.

Am i correct?
Regards,
Gaurav