Quote:
Snakes molt their skins regularly, for the purpose of regenerating skin worn by ground contact and for eliminating parasites, like ticks and mites, and this made ancient people venerate the snake as a symbol of resilience and healing.
A. for the purpose of regenerating skin worn by ground contact and for eliminating parasites, like ticks and mites, and this made ancient people venerate
B. resulting in the regeneration of skin worn by ground contact and by the elimination of parasites, such as ticks and mites, making ancient people venerate
C. so as to regenerate skin worn by ground contact and to eliminate parasites, such as ticks and mites, and these shed snake skins made ancient people venerate
D. in order to regenerate skin worn by ground contact and for the purpose of eliminating parasites, such as ticks and mites, and ancient people venerated
E. thereby regenerating skin worn by ground contact and eliminating parasites, like ticks and mites, and causing ancient people to venerate
Official Explanation
Split #1: listing examples. On the GMAT, it is forbidden to begin a list of examples with "like." We need to use the idiom "such as." In discussing the parasites, choices (A) & (E) make the mistake of using "like ticks and mites," so these two are incorrect.
After this split, we are left with (B) & (C) & (D).
Choose (B) is wordy. It changes the action "regenerating" into a noun, which makes a sentence less direct and more wordy. It places two things in parallel that don't necessarily belong in parallel: the elimination of parasites seems a second purpose, along with regenerating the skin; it is not a second means of regenerating the skin. Because of this logical mistake, (B) is incorrect.
Choice (C) has the elegant structure of two infinitives in parallel after the "so as" structure, and the second half is logical clear. This is promising.
Choice (D) repeats the faulty parallelism of the prompt: in order to do X and for the purpose of doing Y. That is not proper parallelism. Also, the simple "and" at the end makes that fact look like a tack-on extra: this structure obscures the logical connection between this fact and the rest of the sentence. For these reasons, (D) is incorrect.
Choice (C) is the best answer.