Question

Explain why it is better to not use rhetorical questions in a research paper?

Answer 1

Rhetorical questions carry the purpose of persuasion, which you obviously don't need in a research paper, where everything is based on fact. This usually applies in the case of discursive essays, or narrations. Plus, an audience listening to a research paper will probably only be interested in the information strictly, and will be irritated by rhetorical questions. 

Answer 2

A research paper is fact and nothing but the fact. A research paper is just giving information about a topic. However, rhetorical questions are used to persuade the reader to believe or agree with something, mainly in a discursive essay; but in a research paper, you aren't persuading, you are educating.