Scientists say that each of the photographs taken of the Ares Villas plain by the Mars Pathfinder indicate the overwhelming extent to flooding on the planet billions of years ago and the degree that rocks were scattered by its force.
A. indicate the overwhelming extent to flooding on the planet billions of years ago and the degree that
B. indicate that the extent of the floods on the planet billions of years ago was overwhelming and the degree to which
C. indicate the overwhelming extent of the floods on the planet billions of years ago and the degree to which
D. indicates the overwhelming extent of the flooding on the planet billions of years ago and the degree to which
E. indicates the overwhelming extent to flooding on the planet billions of years ago and the degree that

I knew that the use of 'indicate that' is correct but here choice B is wrong. Could you please discuss which one is right and why?

I'm just taking a stab at this but....If you look at the subject "EACH of the photographs". You will see that it is singular. Therefore to say each of the photographs indicate is incorrect. It needs to be "indicates".

I suspect that D is correct. Could you confirm this and does it make sense?

first of all, no. "indicate" is incorrect, because the SUBJECT is "EACH of the photographs". that subject is singular, so you need a singular verb, "indicates".

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here is a big, huge, important principle for you to heed:
just because one form of an idiom is correct, you can't infer that OTHER forms are INCORRECT.
many words / idioms are perfectly well used in two or more ways.
"indicate" is one of these. you can indicate THAT (subject + verb), or you can indicate (NOUN).
both are fine.
unfortunately for you, the correct answer to this problem, (d), uses the other correct version.

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(a)
* "each" is singular, so "indicate" is wrong.
* "extent TO" is unidiomatic; it should be "extent OF".
* "degree THAT" doesn't work. since things happen TO a degree, you have to preserve this preposition; therefore, you have to say "degree TO WHICH".

(b)
* "each" is singular, so "indicate" is wrong.
* not parallel.
the second part, "the degree to which...", is a NOUN PHRASE centered on the noun "degree". to make this parallel, the first part should be another noun phrase, centered on the noun "extent". since this better parallelism is present in other choices, this choice is wrong. NEVER, EVER, choose an answer choice with parallelism that is inferior to the parallelism in other choices.

(c)
* "each" is singular, so "indicate" is wrong.

(d) = correct
note the proper parallelism.
note the proper SV agreement.

(e)
* "extent TO" is unidiomatic; it should be "extent OF".
* "degree THAT" doesn't work. since things happen TO a degree, you have to preserve this preposition; therefore, you have to say "degree TO WHICH".

Thanks a lot Ron for clearing my doubts. OA is D.

I'm glad it helped!

_________________
Ben Ku
Instructor
ManhattanGMAT

Ron,

As you said "extent to" is unidiomatic. Is the usage of "extent to which" is right or wrong. I've seen this usage in many questions.

Thanks!

GeeMate.

Hi Ron,

Ans choice (b),

the second part, "the degree to which...", is a NOUN PHRASE centered on the noun "degree". to make this parallel, the first part should be another noun phrase, centered on the noun "extent". since this better parallelism is present in other choices, this choice is wrong.

Can you give an example? how to make it parallel? I still can't see the parallelism error here.

Thanks

the best way to make it parallel is to make it look like (d), which is the correct answer.

note that (d) has
* the overwhelming extent...
* the degree...

while (b) has
* that the extent is...
* the degree...

(d) is definitely more parallel.

Thanks for all the great explanation..

The correct sentence is:

Scientists say that each of the photographs taken of the Ares Vallis plain by the Mars Pathfinder indicatesthe overwhelming extent of the flooding on the planet billions of years ago and the degree to which rocks were scattered by its force.

Why” its force” refers to “rocks” in the clause “rocks were scattered by its force”? How to interpret the single/plural difference here? Thanks~~~

it doesn't; it refers to "flooding".
logically, the only thing in the sentence that would have had enough force to scatter a bunch of rocks was the flooding. therefore, "it(s force)" refers to the flooding.

why did you think it had to refer to the rocks?