Hello Everyone!
We’ve got a list.
parallelism! Any time you see a list on the exam, that means there will be a few unparallel options that you’ll be able to quickly dump, and that will help us get to the right option even faster.
So what could the parallel structure be here?
Permeates, washes, and replaces
-or-
Permeating, washing, and replacing (but there are some problems with this one...more to come on that later)
Let’s see how each answer holds up:
(A) which
permeates the bone,
washes away its organic components, and
replaces them →
CORRECT(B) which
permeates the bone,
washes away its organic components, and those are
replaced →
INCORRECT(C) which
permeates the bone,
washing away its organic components, to be
replaced →
INCORRECT(D)
permeating the bone,
washing away its organic components, to be
replaced → INCORRECT
(E)
permeating the bone,
washing away its organic components
and replacing them →
INCORRECTSo why else is option E incorrect, even though it uses parallel structure? The GMAT requires the use of the serial comma (aka the Oxford comma) for every item in a list, including the last item in a list of 3+ items. Answer E doesn’t use a serial comma for the third item, so it’s wrong.
But even more fundamentally, (options D and E), insert “permeating” as an -ing modifier right after the comma, which opens up a confusing ambiguous reference because “permeating” could mean that:
1) groundwater permeates the bone
2) the action of groundwater permeates the bone
3) or even the fossilization through the action of groundwater permeates the bone
A is both parallel, and retains the intended message.
Don’t study for the GMAT. Train for it.