California4jx wrote:now that I know the correct answer, it all makes sense, but can anyone help explaining the reason behind it ?
Either X or Y
X or Y must be logically and grammatically parallel
"to improve" parallels " to ward off"
Only "D " adheres this idiomatic construction
Few other errors:
In A, genes' is incorrect
A and B: Animal and plants..spliced looks as if "animals and plants" splice on their own..
In C, "the splicing " is a gerund and what we need is a verb "splicing"
But, overall major error tested is "parallel and idiomatic construction"
