The first one is the one that English teachers look for. Although a professional research paper is important, it can be accomplished without multiple sources.
Plagiarism is only the case when that one source is the only writing in your paper, or you didn't cite the source.
As for the length, I can make a pretty strong point in one paragraph.
Explanation: the answer is problem-solution
1. charging an official with a misdeed (a crime): impeachment
2. chosen; appointed (suggest someone for an election, job): nominated
3. to improve; to change: to make into a better quality: amended
4. reverse; change to the opposite position: overturn
5. whether the law or act is constitutional: constitutionality
6. court determination of constitutionality of laws passed: judicial review
