Hi P.! Happy to help you out with this
For a parallel question on Reading Comprehension, the correct answer choice will be the one that most directly mirrors either the concept referred to in the question or the structure of the passage. In this case, the question asks us to find the answer choice that best parallels a concept: the research described in the passage on peptides.
First, let's summarize the research on peptides: Belcher (one of the researchers) had conducted research on abaolones that discovered a crystallization property of a certain peptide. Belcher and Hu then applied this finding to semiconductor materials and building nanoscale electronics, and since there was no known peptide to accomplish this purpose of crystal growth, they grew and tested one billion different peptides with three semiconductor materials. Once they determined the characteristics that may contribute to the peptide's ability to bind to the crystals, they created additional peptides.
Let's now abstract the aspects of the research that need to be paralleled to the case of volatile oils in the answer choice:
1. Research conducted in a different field with applications to the field of interest
2. Creating/synthesizing other similar materials (in the passage, peptides, and in the answer choice, volatile oils) based off of the original findings to see how they apply to the field of interest
Answer choice (D) starts off strong because it describes a finding in one field of interest (fruit trees) and how it may be applied to another field of interest (human medical applications). However, answer choice (D) is incorrect because this group of researchers does not synthesize similar volatile oils but only examines existing similar oils. In the passage, one critical part of Belcher and Hu's research is that they synthesized new peptides for the new field of interest. Since answer choice (D) does not mention synthesizing new oils, it is incorrect.
Answer choice (E), by contrast, correctly parallels the research described in the passage. First, the group of researchers extrapolate findings from one field (trees and fungal infections) to a new field (human medical applications and antibacterial activity). Second, unlike answer choice (D), the researchers in answer choice (E) synthesize similar oils to apply the research to the new field, as the author described Belcher and Hu doing in the passage.
To sum up, for a parallel question, we want to ensure that all relevant aspects of the concept or passage are mirrored in the answer choice. In this case, answer choice (E) describes a situation that mirrors the important aspects of Belcher and Hu's research, whereas answer choice (D) fails to mirror one important aspect.
I hope this helps, and let me know if you have any other questions!
