On Earth, among the surest indications of sunspot cycles are believed

The important thing here is to note what the pronoun ‘their’ in the un-underlined part points to. Unfortunately, in C it refers to the sunspot cycles by virtue of proximity, while it should refer to the trees, which is what E does and thus outdoes C.
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Ok I've cracked it. Answer is E. My logic was right but I comitted a mistake. The last phrase doesnt modify indications but it modifies the rate of growth. So C is ruled out & hence E wins.

For further clarification try to rephrase the sentence as:

The rate at which trees grow, as seen in the rings visible in the cross sections of their trunks, is believed to be among the surest indications on Earth of sunspot cycles.

This tells us why E is right.

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 this sentence is that the rate at which trees grow, as seen in the rings visible in the cross sections of their trunks is believed to be among the surest indications on Earth of sunspot cycles.

Concepts tested here: Subject-Verb Agreement + Meaning + Modifiers + Grammatical Construction + Idioms

• In a “noun + comma + phrase” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.
• If "rate" is used as a noun "rate + that + clause + at", "rate + of + noun", "noun + rate", and "rate + at which + clause" are the correct idiomatic constructions.

A: This answer choice incorrectly uses the plural verb "are believed" to refer to the singular noun "rate". Further, Option A incorrectly uses the unidiomatic construction "rate (noun) + that + clause"; remember, if "rate" is used as a noun "rate + that + clause + at", "rate + of + noun", "noun + rate", and "rate + at which + clause" are the correct idiomatic constructions.

B: This answer choice incorrectly uses the plural verb "are" to refer to the singular noun "rate".

C: This answer choice incorrectly modifies the noun "the surest indications of sunspot cycles" with "as seen in the rings visible in the cross sections of their trunks", illogically implying that all of the surest indications of sunspot cycles are seen in the rings visible in the cross sections of tree trunks; the intended meaning is that one of the surest indications of sunspot cycles - the rate at which trees grow - is seen in the rings visible in the cross sections of tree trunks; remember, in a “noun + comma + phrase” construction, the phrase must correctly modify the noun.

D: This answer choice fails to form a complete sentence; as "believed" and "seen" are past participles acting as modifiers, there is no active verb to act upon the subject "the tree growth rate".

E: Correct. This answer choice acts upon the independent subject noun "the rate" with the active verb "is believed" to form a complete thought, producing a complete sentence. Further, Option E correctly refers to the singular noun "the rate" with the singular verb "is believed". Moreover, Option E correctly modifies the noun "the rate at which trees grow" with the phrase "as seen in the rings visible in the cross sections of their trunks", conveying the intended meaning - that one of the surest indications of sunspot cycles - the rate at which trees grow - is seen in the rings visible in the cross sections of tree trunks. Additionally, Option E correctly uses the idiomatic construction "rate + at which + clause".

Hence, E is the best answer choice.

To understand the concept of "Phrase Comma Subject" and "Subject Comma Phrase" on GMAT, you may want to watch the following video (~1 minute):



All the best!
Experts' Global Team
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I'm going with E in this one.

A and B present subject-verb agreement problems. They also distort the intended meaning of the sentence.
I think that the problem with C is that "as seen in the rings visible in the cross sections of their trunks" should modify the rate at which trees grow rather than sunspot cycles.

sondenso already pointed out the subject/verb agreement issue with A and B, but I wanted to point out the (hilarious) implications of the placement of the phrase "on earth." In A, B, and C the meaning is slightly different from what we want-- these choices imply that "here on earth" we believe something (...as opposed to the Martians who believe something else?). Often if you see an entire phrase lifted and placed somewhere different in the other answer choices, it's a red flag to check for modifier issues.

The intended meaning is that "out of all of the indications on Earth, this particular indication is the surest." Both D and E correctly place the phrase "on Earth" after "indications," where it belongs.

As several others pointed out above, the non-underlined pronoun "their" means that we must have the plural antecedent "trees." Additionally, D is missing a verb! The past participle "believed," while it looks exactly like the simple past tense "believed" CANNOT function as a verb in this situation. We use the idiom "believed to be" in the following situation:

She is believed to be the best runner in the class.
(OTHER PEOPLE--who are unspecified in this sentence-- believe that SHE is the best runner)

...or...
Stella, believed to be the best runner in her class, won the competition.
(Here "believed" functions as it does in choice D--as a modifier describing Stella)

If we use "believed" as a simple past-tense verb, the function of that verb and the required structure changes:

She believed Carl.
(SHE is the one doing the believing, and CARL is the one being believed)

Choice E (while to my ear horribly wordy) correctly matches the subject/verb, uses the correct pronoun antecedent, and places modifiers correctly. This is another great case for "get rid of the wrong ones" instead of "find the one that sounds good."

On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow, as seen in the rings visible in the cross sections of their trunks.

On Earth, among the surest indications (...)
Among the surest indications on Earth (...)

The two sentences seem to say the same thing, but actually there is a difference.
"On Earth," refers to the whole thing after, not only to the indicator, as it should.

So "among the surest indications of sunspot cycles are believed to be (...)" <== all this is modified by "On Earth", so it seems that on another planet this indicators are not believed to be accurate.
On the other hand "Among the surest indications on Earth (...)" says that on Earth we have some indications, and among those tree growth is accurate.

Hope I've explained myself well!
The OA is E.

C says: On Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles ------------>tends to say that "all this believing" is "on earth" and that "on some other planet" the belief is different !! , not the intended meaning

ALSO "as seen in the rings visible in the cross sections of their trunks" gives wrong meaning in option C !!

A. On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow
B. On Earth, among the surest indications of sunspot cycles are, it is believed, the rate of tree growth
>>A & B are out because of "...cycles are".

C. On Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles
>>I ruled out C since the sentence ends with "as seen in the rings...". The part preceding it must make logical sense. "as seen ..." is too far away to refer to "rate at which trees grow".

D. Among the surest indications on Earth of sunspot cycles, believed to be the tree growth rate
>>Like a commitment-phobic boyfriend, D can't make up its mind, eliminating both "is" and "are". The effect of this removal is that "believed to be the tree growth rate" sounds like the definition of "sunspot cycles".

E. Among the surest indications on Earth of sunspot cycles is believed to be the rate at which trees grow[/quote]
>>Not a great sentence, but hey, this is the answer.

What's wrong with B?
That was my choice...

Among other issues, B has most prominently a subject-verb agreement issue. The rate is the subject and so, the verb should be is, and not are. Basically the sentence should be:

....among the surest indications of sunspot cycles is....

p.s. This is basically an inverted sentence. Our book EducationAisle Sentence Correction Nirvana discusses inverted sentences, its application and examples. If you can PM you email-id, I can send you the corresponding section.
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The first thing I noticed is the difference between "are" and "is" in the answer choices. To figure out which one it is, switch around the first part of the sentence; read the sentence as "the rate that trees grow are believed to be among the surest indications of sunspot cycles". This quick method reveals that the use of "is" is required because "the rate" is singular. That eliminates A and B. Next, looking at C, D, and E, D is a quick elimination because there is no verb to complete the sentence; "is" has to be in the sentence, but there is not a verb at all, therefore this is an incomplete sentence. This leaves C and E as the remaining answer choices. This is a more subtle difference, but C is eliminated after realizing that "as seen in the rings visible in the cross sections of their trunks" is actually modifying "indications of sunspot cycles", and that makes this choice illogical. This leaves the remaining answer choice, E, correct because it uses "is" and has the correct object being modified ("trees").

In my opinion-

X is believed to be Y is not same as Y is believed to be X-

Jon is believed to be a good writer
Good writer is believed to be Jon

See these 2 sentences changes the meaning drastically.


As per meaning of sentence among the surest... are believed to be rate at which tree grow.
Hence C is wrong and E is correct

A participial phrase appearing at the end of the passage, if not set off by comma, modifies the noun just in front; However, if the participial phrase is set off by a comma from the previous noun, then it need not modify that noun and will usually modify a distant noun, mostly the subject. See the following examples.

1. The rape-accused nervously watched the eyewitness, alarmed by her revelations -- here ‘alarmed by’ modifies the rape accused and not the eyewitness
2. We often hear about politicians corrupted either by money power or muscle power. --- Here ‘corrupted by ‘modifies politicians

C. on Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles, as seen in the rings visible in the cross sections of their trunks. --- Here, because of the comma before 'as seen', the modifier need not necessarily modify the sunspot cycles. It can very well modify the rate

E. Among the surest indications on Earth of sunspot cycles is believed to be the rate at which trees grow
But in ‘E” the problem seems to be that of ‘Earth of sunspot cycles’, which means to imply we have some kind of an earth that is specifically called the ‘earth of sunspot cycles’. This is illogical in the least if not ungrammatical altogether.
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On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow,
as seen in the rings visible in the cross sections of their trunks.

A. On Earth, among the surest indications of sunspot cycles are believed to be the rate that
trees grow
that is a wrong modifier here which changes the meaning
B. On Earth, among the surest indications of sunspot cycles are, it is believed, the rate of tree
growth
it is refering to what thats a main error in this option
C. On Earth, the rate at which trees grow is believed to be among the surest indications of
sunspot cycles
this sentence changes the intended meaning of the sentence
D. Among the surest indications on Earth of sunspot cycles, believed to be the tree growth rate
Verb is missing
E. Among the surest indications on Earth of sunspot cycles is believed to be the rate at which trees grow
This option delivers the intended meaning as well as it also rectifies the main modifier error created by "that" in the main sentence by using "at which"

Press +1 kudos

On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow, as seen in the rings visible in the cross sections of their trunks.

First thing to know is that no conjunction has the power of making a list plural except "AND". "Amongst the many X's" is always singular
since "AMONG THE MANY INDICATIONS" is the subject of the sentence, the SUBJECT-VERB agreement dictates that we use a singular verb. So we have to use "is" and not "are"
Secondly the meaning of the sentence imply that sunspots are seen "indirectly" on earth for example :-as the growth rings of trees.
A SUNSPOT CANNOT EXIST ON EARTH ON ITS OWN. BUT THE EVIDENCE OF SUNSPOTS CAN EXIST AS SEEN IN THE TREE RINGS.


A. On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow
WRONG:- incorrect SV agreement

B. On Earth, among the surest indications of sunspot cycles are, it is believed, the rate of tree growth
WRONG:- incorrect SV agreement

C. On Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles
WRONG:- add this one to the original sentence and you will see that it implies "sunspots can be in seen tree growth rings."

On Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles as seen in the rings visible in the cross sections of their trunks
ABSURD MEANING:- Trees captured sunspots and now those sunspot are seen in the trees ring.

D. Among the surest indications on Earth of sunspot cycles, believed to be the tree growth rate
WRONG:- This one has no auxiliary verb at all . It directly jumps to the main verb "believed"
To make a correct verb phrase we need auxliary verb + main verb = correct verb phrase. We need "is" to make this sentence grammatically correct.

E. Among the surest indications on Earth of sunspot cycles is believed to be the rate at which trees grow (as seen in the rings)
CORRECT:- Perfect !! correct SV agreement. Correct meaning "Rate" can be "seen" in the relatively thickness of the tree rings. THIS ONE IS BETTER THAN OPTION C BECAUSE SUNPOT CANNOT BE SEEN IN A TREE RING BUT RATE CAN BE SEEN IN A TREE RING (AS IN THICKER RING MEANS MORE GROWTH , THIN RING MEANS LESS GROWTH.

hello expert ,
please explain the reasoning behind the correct as well as the wrong answers,

thanks

A,B: Eliminate because plural verb "are" does not match with singular subject "rate".

D: No verb in the main clause

C and E are grammatically alright. But C expresses a wrong meaning: On earth, it is believed. "On earth" wrongly refers to "is believed". In E "on earth" correctly refers to "indications".

Hello experts,

Option C is wrong because of [comma the rate at which trees grow is believed to be among the surest indications of sunspot cycles comma] construction?

In C, "on earth" is used as an adverbial modifier referring to the verb "is believed" (implying that on earth it is believed, but may not be on other planets).

Instead "on earth" must be used as a noun modifier referring to "indications".