Prospecting for gold during the California gold rush was a relatively easy task, because of erosion, prehistoric glacier movement, and ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach for anybody with a pan or shovel.

A. because of erosion, prehistoric glacier movement, and ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach for
B. because of erosion, prehistoric glacier movement, and volcanic activity that thrust ancient, gold-bearing riverbeds to the surface, and putting gold literally within reach of
C. owing to erosion, prehistoric glacier movement, and volcanic activity that had thrust ancient, gold-bearing riverbeds to the surface, and putting gold literally within reach of
D. since erosion, prehistoric glacier movement, and volcanic activity that thrust ancient, gold-bearing riverbeds to the surface, putting gold literally within reach for
E. since erosion, prehistoric glacier movement, and ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach of

Answer: E

I eliminated A and D because I thought that "within reach of" is the correct idiom NOT "...within reach for anybody..." ??
I am not sure why we use since and not because?

I would add one more question here:

isn't SINCE used for TIME REFERENCE on GMAT? In my opinion SINCE here changes the meaning of the sentence. Please clarify

Also don't you think as per GMAT E has a comma missing between ACTIVITY and PUT.

"Since" can mean "in the time from ___ until now." But it can also mean "due to."

"Within reach of" and "within reach for" is not necessary in order to solve. I actually think this idiom could go either way.

Can you please tell why E better than A? I don't see any difference in A and E other than the Since/because of and the reach of / reach for

Thanks

A is wrong because we have: "because of (nouns in a list) put ..."
This is an awkward construction, because the word "of" is a preposition, and you cannot follow a preposition with a clause. You CAN, of course, follow a preposition with a noun, or even a noun list, but here these nouns are acting as the subject of the verb "put." This makes a clause; hence, "of" is awkward.

Sentence structure in all but E is flawed. ( because and since are secondary issue)


Prospecting for gold during the California gold rush was a relatively easy task, because of erosion, prehistoric glacier movement, and ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach for anybody with a pan or shovel.

A. because of erosion, prehistoric glacier movement, and ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach for

After we remove fluff, the core is :

Prospecting for gold..........was ....easy task, because of x , y and z put gold literally within reach for anybody

We cant say because of x , y and z put.........hence wrong
we need a reason and , only because can work,but not because of.

One more problem is reach for is unidiomatic.

B. because of erosion, prehistoric glacier movement, and volcanic activity that thrust ancient, gold-bearing riverbeds to the surface, and putting gold literally within reach of

same problem

Prospecting for gold..........was ....easy task, because of x, y and z , and putting gold within reach of...........

Both these bold face make the sentece unidiomatic




C. owing to erosion, prehistoric glacier movement, and volcanic activity that had thrust ancient, gold-bearing riverbeds to the surface, and putting gold literally within reach of

Prospecting for gold..........was ....easy task, owing to x, y and z , and putting gold within reach of...........flawed



D. since erosion, prehistoric glacier movement, and volcanic activity that thrust ancient, gold-bearing riverbeds to the surface, putting gold literally within reach for

Prospecting for gold..........was ....easy task, since x , y and z, putting gold literally within reach for anybody..........sentence structure is just too bad........I mean there is no connection between parts.



E. since erosion, prehistoric glacier movement, and ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach of

Prospecting for gold..........was ....easy task, since x , y and z put gold literally within reach of anybody........

Perfect .....smooth sentence structure, connecting parts appropriately
the second part gives reason why prospecting for gold was easy

The use of "Because" is wrong here because that would imply causality...right? this is more of an "in that" sentence...correct?

Causality is definitely appropriate in this sentence, which is why either "because" or "since" can be used. This is definitely not an "in that" sentence, primarily because "in that" is not in any of the answer choices! Don't try to rewrite a sentence to be something that doesn't show up as an answer choice..

_________________
Tim Sanders
Manhattan GMAT Instructor

ok, let me knew your thoughts on this
a) is wrong b/c if you look at the core of the sentence you have "b/c of x, y and z PUT GOLD WITHIN REACH FOR"
that doesn't make sense...also the idiom is wrong
b) is wrong b/c the list of nouns isn't parallel. also, the construction "b/c of x,y and z AND PUTTING GOLD..." is wrong as well
c) again the "and putting part" doesn't tie in... how can "prospecting putting"
d) list not parallel. idiom is wrong
e) list is parallel. idiom is correct

if you could share what is specifically wrong with the "b/c of ... and putting" construction types...gramatically speaking...that would be helpful. thanks.

well, when you see a structure ending with "and", you know that you're dealing with parallelism.
so your job is to determine the other part(s) of the parallel structure, and to check whether the parallelism is legitimate.

don't forget -- for a parallel structure to work properly, you have to have two different kinds of parallelism:
1) Parallel GRAMMAR
2) Parallel IDEAS -- i.e., the elements placed in parallel must be the same type of thing/idea/concept.

in choice (c)
when you look at the construction that ends with "and putting...", you have to go find some construction to which this could be parallel.
if you look, you'll find that the only such construction is
owing to erosion, prehistoric glacier movement, and volcanic activity that had thrust ancient, gold-bearing riverbeds to the surface.
the problem is that this IDEA isn't parallel to the IDEA of
putting gold literally within reach for anybody with a pan or shovel.
i.e., the first of these is a general description of why prospecting was easy, while the second describes a consequence of the thrusting of the riverbeds to the surface.

so there isn't actually a grammatical mistake here -- it's just that the parallelism doesn't make logical sense.

(for instance, to see the logical way in which parallelism is supposed to work, just write a really simple parallel sentence, e.g.,
i enjoy running and swimming.
--> running = an activity that i enjoy
--> swimming = an activity that i enjoy
note that these are actually parallel ideas, in addition to their grammatical parallelism.

I agree with all your explainations above regarding parallelism around and...

but if i closely look at choice e there is 'and' too and this 'and' parallels all the reasons such as erosion, pre-historic glacier movement and Z

Z here is volcanic activity... but the way it is presented totally confuses me

ancient, gold-bearing riverbeds thrust to the surface by volcanic activity put gold literally within reach of

comma after ancient also a problem to me

Please explain this

“ancient” and “gold-bearing” both modify the riverbeds; the comma is there to keep you from thinking the gold was ancient. As for the parallelism, there are three things that are parallel, NONE of which are “volcanic activity”. The parallel elements of course are joined by commas and an “and”:
erosion
prehistoric glacier movement, and
ancient, gold-bearing riverbeds thrust to the surface by volcanic activity

_________________
Tim Sanders
Manhattan GMAT Instructor

I eliminated E first time as i understood it as
Prospecting for gold during the California gold rush was a relatively easy task since erosion, prehistoric glacier(Or from certain point of time....)
Doesnt it change the meaning of original sentence?

not an issue here, since the other four choices are all grammatically incorrect -- they either have bad parallelism or aren't sentences at all (run-ons or fragments).

if there is only one correctly written sentence -- and the others are all INCORRECT -- then (slight) meaning changes are allowed.
you only have to get into the issue of preserving the exact sense of the original sentence when there are two or more correctly written sentences.

Pls correct me if I am wrong.

Here "reach for" means that the gold is trying to reach for the people.

When we use " reach of", it indicates that the gold is now with in the reach of the people, hence correct.

Thanks.