It is unclear whether chimpanzees are unique among nonhuman

[RonPurewal]

you're trying to do something that's impossible here. you can't "put additional words back" into these sentences!

basically, there are 2 possibilities:

1/
you have the construction "more X than Y", in one place.

OR

2/
the "Y" part was ALREADY MENTIONED EARLIER, so, the second part just contains "more X".

the point is that you can't turn #2 into #1.
if you have situation #2, then, you CAN'T turn that into "more X than Y" without creating redundancy and/or incorrect mechanics—unless you actually re-write the entire sentence so that it looks like #1.

[KevinS587]

Well, that makes sense! I'm so appreciate your explanation. I think I may have some trouble here but yeah, finally get it.

Thanks Ron! I've just got my 760 the day before yesterday, and all your posts help me get this. Have a nice day!

[RonPurewal]

congratulations!

[YuC257]

Hi, Ron. I have a question. In choice C, what does the pronoun "they" in "if they were studied in as much depth" refer to? I think it refers to "other animals" accordingly to logic, but the Words, "other animal" , are in a prepositional phrases. is that meaningful？

[Sage Pearce-Higgins]

You're right, it refers to other animals. Why do you think a pronoun can't refer to a noun in a prepositional phrase? It would be pretty hard to communicate in English if we couldn't refer to nouns in prepositional phrases, both when speaking it and writing it.