The discovery that Earths inner core rotates independently of and more

GMATNinja
VeritasKarishma

am I wrong in saying that D and E are sentence fragments? I mean there is no main verb for the discovery subject

Yup, that's correct. The verbs in these two options ("is" and "are") are trapped within the "that" clause, so we don't actually have a main verb for the subject ("discovery").

Bunuel, can you please tag this as a GMAT Prep question? It appeared in my mock today.

Thank you.

_____________________
Done. Thank you!

GMATNinja
EMPOWERgmatVerbal

While i now understand the reasons why option (b) is incorrect, the highlighted portion in the option (a) continues to throw me off.

The discovery that Earth's inner core rotates independently of and more quickly than Earth's outer layers is responsible for advancing studies of the flow of heat from the inner through the outer planet and of the formation and periodic reversal in direction of Earth's magnetic field.

Is ellipsis at play here? Core is implied? Doesn't seem like a very natural construction

Thanks for your question rishi02!

While we do agree that this sentence is incredibly long-winded, which might make it confusing for readers, option A is still the best option of the 5 we have to choose from. Since we're only talking about one planet, we can imply that when we refer to the "inner" planet, we're talking about the core. Repeating mention of the core would be more important if we were comparing/contrasting more than one planet.

This is one of the ways the GMAT can be tricky - long, complex sentences with a lot of parts can distract us from the core concepts we need to focus on, which in this case are parallelism and logical construction.

We hope that helps! Feel free to tag us at EMPOWERgmatVerbal if you have any other questions!

rishi02

While i now understand the reasons why option (b) is incorrect, the highlighted portion in the option (a) continues to throw me off.

The discovery that Earth's inner core rotates independently of and more quickly than Earth's outer layers is responsible for advancing studies of the flow of heat from the inner through the outer planet and of the formation and periodic reversal in direction of Earth's magnetic field.

Is ellipsis at play here? Core is implied? Doesn't seem like a very natural construction

The sentence is sort of structured as follows:


The discovery... is responsible for... studies

1) of the flow of heat...
2) of the formation...

Hope that helps.

Hello rishi02,

We hope this finds you well.

To answer your query, the phrase "from the inner through the outer planet" does not directly refer to the "core"; rather, it simply conveys that the studies that were advanced by a discovery regarding the Earth's inner core are concerned with how heat moved from deeper sections of the planet to outer sections.

We hope this helps.
All the best!
Experts' Global Team

while talking about parallelism in B]

we see '' discovery is responsible for advancing studies of how heat from the inner core flows and the formation.....

the phrase followed after preposition ''of'' should be a noun?

I heard from somewhere that ''how heat flows from the inner core'' behave as a noun'' Please guide.


if we ingnore the word 'how' is parallelism justified? do we really need another 'of' before the 'formation' to make it parallel?

Can't we assume 'of' to be commom for the items in the list


Moreover, is oxford comma rule strictly followed on GMAC. can we use it for elimination?

The words who/what/where/when/why/how have two different functions in the English language in general:
1/ Starting a question
2/ Starting a noun clause (= a clause—i.e., with a subject+verb in it—that acts as a noun)
The noun clause here, by the way, represents the answer to the corresponding question. E.g., in the sentence "I know what you're thinking", the noun clause "what you're thinking" represents the answer to the question "What are you thinking?"



GMAT SC sentences, however, are NEVER questions—they're ALWAYS declarative statements. Accordingly, in GMAT SC, these words who/what/when/where/why/how will introduce noun clauses.


There are some additional words of this type that cannot introduce a valid question—or that can only do so in heavily stylized/poetic/dramatic language—and that therefore MUST therefore begin a noun clause even in the more general English language.
E.g.,
whether (...absolutely CANNOT begin a question; this word must begin a noun clause)
whatever/whoever/whomever/however/wherever/whenever (...can only begin questions in poetic/dramatic speech; otherwise must begin a noun clause)

The mechanical parallelism is workable either with or without the second "of":
studies of X and Y
studies of X and of Y

In this context, it's better to use two instances of "of", for at least two reasons:

• These parallel parts are so long that, without the additional cue provided by the second "of", it's very difficult to recognize them in one read-through of the sentence.

• There's a fairly subtle distinction in meaning: "Studies of X and Y" implies that X and Y are covered together in each of the studies, whereas "studies of X and of Y" implies that there are, separately, studies of X and studies of Y.
In this case the 'X' and the 'Y' represent two altogether different scientific subjects, so the latter meaning is more sensible in context.
(No official SC problem will require the consideration of subtleties on this level.)





GMAC follows the convention of inserting this comma before "and"/"or" in lists of three or more parallel items.
X, Y, and/or Z (...NOT "X, Y and/or Z")

I don't think you'll ever have the opportunity to use this for elimination. GMAC will definitely NOT write wrong answers containing these sorts of lists WITHOUT the last comma.

In fact, if you see something that LOOKS like that, you should consider it carefully because it's probably a different type of construction altogether.

E.g.,
In 2010 I married Sarah, my soul mate and my best friend.
This is "X, Y and Z" in which the "Y and Z" part (my soul mate and my best friend) is a modifier of "X" (Sarah). Obviously I didn't marry three different women at once!

Looks like Ron (hi, Ron!) beat us to this one, but in case it helps, check out this post for our take on the parallelism in A and B.

of course, one can't marry three women at once!

Thanks for your help

can we say that oxford comma is used incorrectly in B C and E?

Well, (C) and (D) are out right away because of the subject-verb agreement error (The discovery... are responsible...).

The GMAT is pretty lenient when it comes to comma usage, and we've seen OAs with a comma separating just two things in a list. Generally speaking, if you're unsure about a comma, you're MUCH better off looking for other decision points.

In this case, the more important issue is the parallelism in the remaining choices:

(A) The discovery is responsible for advancing studies (1) of the flow of heat from the inner through the outer planet and (2) of the formation and periodic reversal in direction of Earth’s magnetic field.

(B) The discovery is responsible for advancing studies of (1) how heat from the inner core flows through the outer planet, and (2) the formation and periodic reversal in direction of Earth’s magnetic field

(E) The discovery is responsible for advancing studies (1) of the flow of heat from the inner through the outer planet and (2) of how Earth’s magnetic field forms and the periodic reversal of its direction

The parallelism in choice (A) is the best ("... studies of X and of Y..."), and, as a result, the meaning is clearer and easier to follow in (A) than in (B) and (E).

For more on that, check out this post: https://gmatclub.com/forum/the-discover ... l#p2419284.

"ABC" Sentence Template: The discovery that A has led to studies of B and of C.

The discovery that Earth’s inner core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of the flow of heat from the inner through the outer planet and of the formation and periodic reversal in direction of Earth’s magnetic field.

Option Elimination - This question plays with our minds. Long sentences, relative clauses, prepositional phrases, and SVs. If we stick to the basics, the question is comparatively easy.

(A) core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of the flow of heat from the inner through the outer planet and of the formation and periodic reversal in direction of Earth’s magnetic field.
Basic structure -
The discovery (subject) relative clause (which is a noun modifier modifying "the discovery") is (verb) responsible for advancing studies prepositional phrase (of the flow) and prepositional phrase (of the formation). Parallelism around "and". Ok.

(B) core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of how heat from the inner core flows through the outer planet, and the formation and periodic reversal in direction of Earth’s magnetic field -
The discovery (subject) relative clause (which is a noun modifier modifying "the discovery") is (verb) responsible for advancing studies of "the relative clause" (how heat from the inner core flows) and the noun phrase (the formation and periodic reversal). The structure around "and" is not parallel.

(C) core rotates independently and more quickly than Earth’s outer layers are responsible for advancing studies of how heat from the inner core flows through the outer planet, and how Earth’s magnetic field forms and the periodic reversal of its direction - SV issue.

(D) core, rotating independently and more quickly than Earth’s outer layers, are responsible for advancing studies of the flow of heat from the inner through the outer planet, and the formation and periodic reversal in direction of Earth’s magnetic field - SV issue

(E) core, rotating independently of and more quickly than Earth’s outer layers, is responsible for advancing studies of the flow of heat from the inner through the outer planet and of how Earth’s magnetic field forms and the periodic reversal of its direction -
The discovery (subject) noun phrase (the structure of a relative clause is broken) is (verb) responsible for advancing studies of "noun phrase" (the flow of heat from the inner) and of the noun clause (how Earth’s magnetic field forms and the periodic). The structure around "and" is not parallel.