Hi,
I think Ron answered both of your questions well earlier in this post, and I think your confusion stems from confusing a subjective pronoun that replaces a subject in a sentence with a possessive noun.
manassingh - did have a valid question !
Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil, their descendants, popularly known as killer bees had migrated as far north as Southern Texas.
"of African honeybees" is a prep phrase and African honeybees is thus the o.p.(object of prep) . In "their descendants" their seems to refer to the African honeybees, but since the subject is trapped as an o.p "their" doesn't have a true referent.
Their is a possessive pronoun that refers back to "african honeybees" as the antecedent is the only thing to which "their" can refer. The pronoun is just taking the place of the noun honeybees and this problem has nothing to do with the "subject of a clause."
The problem with my brother is that he is just nuts about the GMAT.
In the above example the personal pronoun "he" clearly refers back to my brother. "He" is a subjective personal pronoun in that "he" can take a verb. In this case "subjective" doesn't mean that it must replace the main subject, or "the problem" in this example sentence.
I think the takeaway is that subjective pronouns can act as subjects but don't necessarily have to replace subjects. Further, pronouns replace
nouns and you need to concern yourself with unambiguity to make sure that the pronouns agree. In the original problem "their" was outside the underlined portion and it was abundantly clear that "their" replaced "honeybees."
As for your other question:
Also, will option C be correct if it were reworded as:
In less than the 35 years since African honeybees were released outside Sao Paulo, Brazil, : Using this construction the order of events on the time line is clear
This doesn't work because the earlier event "were released" uses the simple past while the later past uses the past perfect. As a result the time order as defined by verb tense is reversed from what it should be. Ron already explained this in detail so I recommend you check out his posts above but here are some relevant excerpts:
If you were narrating in the present tense, you'd say the following: 'as of today, the bees have migrated as far north as southern texas.' therefore, since this sentence describes a situation in the past (it describes the situation 35 years after the release, which is before the present), you translate all present-tense verbs into the past tense. this turns 'have migrated' into 'had migrated'.
there is no explicit description of the 'second event' you're looking for in this problem, which is what makes it difficult. instead, the 'second event' is the point on the timeline, 35 years after the release of the bees. because the sentence describes a trend whose relevance continues up to and through that point, a perfect tense is appropriate. * choice c: 'the 35 years since' implies that the present is 35 years after the release date. not only does this conflict with the meaning of the original, but it also renders the past perfect (from the underlined part) inappropriate: you'd need present perfect in this case. also, since the release is a point event, it would belong in the simple past.
and
I'm with you on this one; i'd likewise prefer a wording such as 'in less than 35 years after...', because, in my opinion, it better conveys the idea that the migrations took place continuously over the 35-year period. just plain 'less than' seemed to me, and possibly to you as well, to suggest that the migrations might have occurred all at once.
in any case, though, you've got to remember that correctness trumps clarity (and definitely trumps concision as well). therefore, differences in wording, such as this one, are trifling in comparison to actual errors in usage, grammar, diction, or idiom. i think both of us will agree that there is no idiom error in the wording chosen here; it's just a somewhat awkward wording (a situation by no means uncommon on the real test).
I'm pretty much in lockstep with Ron on this one. I don't think it pays great dividends to rewrite these sentences because 1. that's not a practice that will help on the GMAT and 2. you tend to miss the point the problem is making. In this case your new version of the sentence repeated the issue of using "since" vs. "after" and ignored the takeaway regarding the less common use of the past perfect.
Thanks,
Chris