EducationAisle
By the way, what would also be correct is:
A mastodon carcass, which has been thawed only once AND is still fresh, is on display.
So, the second
which may or may not be repeated.
Yes! The primary issue here is clarity. In
EducationAisle's sentence, the two parallel "
which" clauses are very short, and grouped together by the commas that set them off from the rest of the sentence. Even without the second "
which," the parallelism is crystal clear here. If the clauses were significant longer, then the clarity of the parallelism would be lost without the second "
which."
GMAT SC is not just about grammar. It's about (1) grammar, (2) rhetorical construction, and (3) logic & meaning. Parallelism is one of the GMAT's favorite topics, because it's not just about grammar --- it's a structure in which grammar and rhetoric and logic all converge and intertwine. You can't understand parallelism mathematically ---- it's more than the rules can summarize.
Does all this make sense?
Mike