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.
He discover that he might suffer from some mental disorder causing him to react aggressively and with no limits at all,suffering afterwards from the aftermath of his own actions therefore he decides to keep a journal about it for research....
Thoreau has a possitive attitude toward the outdoors and believe that all people should return to nature as salvation for them. He believes that cities are bad for us.