annikaagarwal
Is the usage of "by" in option D correct ?
Further, why is option E incorrect ? Are we eliminating option E basis "being" or are there any other errors to eliminate the same?
GMATNinja bb Bunuel Skywalker18 AjiteshArunYup, the "by" is fine in (D), since the "powerful legs with long feet" are what distinguish the kangaroos from other large mammals.
Here, we have a passive voice verb ("are distinguished"), and the "by" is used to indicate who or what is performing that action. This is a very typical construction -- for example, we could say something like "The platter of 20 burritos was eaten by the GMAT tutor" or "Tim was beaten up by Lou Ferrigno."
As for (E), "being" is indeed a problem because it makes it sound as though the process of being distinguished is ongoing. Does it mean that the kangaroos won't be distinguished from other large mammals until that process is complete? That doesn't make sense -- the kangaroos already have powerful legs with long feet, and that's what distinguishes them from other large mammals.
Also, "other large mammals by powerful legs" is simpler and easier to follow than "other mammals that are large by powerful legs". This unnecessarily wordy construction makes the "by powerful legs" modifier more confusing (at first glance it seems to go with the "that are large" part). It's not necessarily a dealbreaker, but it's another small vote in favor of (D).
I hope that helps!