Sentence Correction

In choice E.

Can't which refer to the former list 'extremes of temperature, precipitation, and storminess' ?especially that it is followed by plural verb are.

Possible antecedents of which clause are two;
1)the list of weather parameters --temperature, precipitation, and storminess--that which clause touches.
i.e, list of nouns--noun 1, noun 2, and noun 3.

2)noun phrase-- extremes of temperature, precipitation, and storminess.
Note in this interpretation, the antecedent is not the list but the noun phrase( of which list is a part ).

Now, if the antecedent of which clause is the former one ( list of weather parameters ), the meaning is illogical--weather parameters by themselves are not the effects; rather extremes of these weather parameters are the effects( as communicated by OA ).

As the first interpretation is downright non-sensical, lets analyze the second interpretation.
Second interpretation, interestingly, is 180 degrees to the first interpretation and thus makes perfect sense.

Now, the question is CAN WHICH CLAUSE JUMP PREP PHRASE in this kind of situation, i.e in a situation in which we have two potential antecedents of which clause, and none has Subject-Verb disagreement issue and in which one interpretation is downright non-sensical while the other interpretation makes perfect sense?

To answer this question to everyone's satisfaction, we have to answer another question: Is there any precedence of this particular situation in official material, since official material is THE ONLY CHANNEL GMAC communicates with us? (There is not ANY OTHER channel).

We don't have such a situation in the under-lined portion of official SCs.
However, we do have such a situation in the non- underlined portion of one of the latest official SC--SC from Exam Pack 2[1];
In this EP2 SC, it seems that the second interpretation is perfectly acceptable to GMAC.

Now counter argument can be made that non-underlined portion is not a good guideline for us to draw conclusion on GMAC's stance on a given issue.
My reply is that overlooking such a fact on such an important concept and that too on one on which GMAC seemed to have maintained its position for long is ,perhaps, not a good idea.
True that non-underlined portion of SCs do not undergo same level of editing as underlined portion of official SC do.
However, latest material offers latest guidelines and offers GMAC latest stance on issues of which only GMAC and not any grammar book can offer solution to.

Having said all this, whenever we have this situation, there are ALWAYS other errors( more readily identifiable) on the basis of which the fate of that answer choice can be decided and thus, this particular concept has NEVER EVER been a deal breaker as is the case with pronoun ambiguity in general.

PS:
[1]

The state religion of ancient China, which came into existence at least as far back as the Han Dynasty (206 B.C. to A.D. 220) and[spoiler] perhaps as early as the Western Zhou Dynasty (1050 B.C. to 771 B.C.), allowed only emperors performing the ritual worship of heaven, perceiving them as special links between the earthly and celestial realms.

A. only emperors performing the ritual worship of heaven, perceiving them as
B. only emperors to perform the ritual worship of heaven, with the perception of them being
C. the ritual worship of heaven to be performed only by emperors, who were perceived as
D. the ritual worship of heaven, performed by emperors only, with the perception of them as
E. the ritual worship of heaven as performed by emperors only, who were perceived to be [/spoiler]

OA C

antecedent of which clause is not ancient China but state religion of ancient China( noun phrase).

Which clause can potentially refer to ancient china or it can refer to state religion of ancient China: one interpretation is downright non-sensical while the other one makes perfect sense.

Similarly, case can be made in favour of which clause modifying not the noun it touches but the noun phrase.
However, in all such cases, there are always other errors, on which it is much better to rest one's judgement.

Similarly, in the SC under discussion, there is another error in E discussing which i think can be even more beneficial.

Long story cut short-
Contrast in A is one intended.
Contrast, in E is not indended.
How?
A) effects( in general) but effects (in general).
E) effects( in general) but effects ( not in general now).
In A, the particularity aspect is in non-essential modifier.
However, in E, the general aspect is in non essential modifier.

A)Discussion of greenhouse effects has usually focused on whether the Earth would warm and by how much, but climatologists have indicated all along that the most obvious effects, and those that would have the largest impact on people, would be extremes of temperature, precipitation, and storminess.

E)Discussion of greenhouse effects has usually focused on whether the Earth would warm and by how much, but climatologists have indicated all along that extremes of temperature, precipitation, and storminess, which are the most obvious effects, are those(effects) to impact the most on people

in A) it is an orange vs an orange,
whereas in E) it is an orange vs a lemon.

Moreover, E also has an unidiomatic issue : extremes are effects to impact the most on people .
people was supposed to be the direct object of to impact.
We, however, have on people(prep phrase) and not people.
Making it people will not help either because in that case most will end up modifying people( meaning change).




Following explanation is not necessary to get to the correct answer choice.
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To get some specific job done, GMAC has a correspondind tool that get that specific job done. For instance,
for causation, we have because, because of, so, thus, therefore, since, as a result, consequently, resultantly etc.
Double causation is incorrect.( Because..., so)or ( because..., thus etc).
Similarly, no indication of cause and effect situation where one mandates is incorrect.

for contemporaneous actions, we have ,ing ing(w/o comma), simultaneously, as(clause), when, while Ving
Similarly, no indication of contemporaneous situation where one mandates is incorrect.

for contrast, we have but, yet, however, although, whereas, while(clause) etc. All these tools essentially perform the task of contrast although there are little nuances that make one much suitable for any specific situation, for instance although vs whereas, i believe, is a genuine split/ distinction. Similarly while clause is much suitable for contrast + contemporaneous situation. However, all these tools necessarily indicate some form of contrast in core.

Double contrast in GMAT SC (for a single contast) is incorrect if both contrasting expressions are conjunctions.( but yet is the most popular one).
However, reinforcing is allowed. for instance but instead, but rather ( conjunction( that shows contrast) + adverb ( that shows contrast and thus reinforces the contrasting aspect of situation)) is perfectly acceptable.

Similarly, no indication of contrasting situation where one mandates is incorrect.
Please note that omitting the contrasting expression( such as but, however) is absolutely acceptable if the contrast still can be communicated properly; it is possible to omit contrasting word/phrase/expression and still maintain contrast in core [A].

Therefore, if there is a contrasting expression in a sentence, then there must be a contrasting sitution in hand.


PS:
[A] we do have official SCs in which there was contrast but no contrasting word/phrase/expression