Dear Friends,
Here is a detailed explanation to this question-
bmwhype2 wrote:
The root systems of most flowering perennials either become too crowded, which results in loss in vigor, and spread too far outward, producing a bare center.
(A) which results in loss in vigor, and spread
(B) resulting in loss in vigor, or spreading
(C) with the result of loss of vigor, or spreading
(D) resulting in loss of vigor, or spread
(E) with a resulting loss of vigor, and spread
Choice A: In this answer choice, the word "which" is incorrectly used to refer to an action. Furthermore, this answer choice fails to maintain the idiomatic structure "either...or" by using the word "and"; this usage also alters the meaning of the sentence by removing the sense of contrast that this sentence demands. Finally, the phrase "loss in vigor" is unidiomatic; the correct phrase is "loss of vigor". Thus, this answer choice is incorrect.
Choice B: This answer choice also uses the unidiomatic phrase "loss in vigor". This answer choice also fails to maintain parallelism between the verbs "become" and "spreading". Thus, this answer choice is incorrect.
Choice C: This answer choice repeats the parallelism error found in Option B. Additionally, the use of the phrase "with the result" is needlessly wordy. Thus, this answer choice is incorrect.
Choice D: Option D maintains parallelism and correct idiom use throughout the sentence and conveys the intended meaning of the sentence. Thus, this answer choice is correct.
Choice E: This answer choice makes the same error of incorrectly using the word "and" in place of "or" that Option A does. Thus, this answer choice is incorrect.
Hence, D is the best answer choice.To understand the concept of "Which v/s That on GMAT", you may want to watch the following video (~2 minutes):
All the best!
Experts' Global Team