So the professor basically has no say so. haha
And so on
For Writing 101 I wrote a paper about the social differences between high school and college, I made a C+. Later I wrote a paper on Batman, I made an A. WTF!
Subjects of papers really don't matter, for this instance, social differences in high school and college and a paper of Batman.
What the professor is looking for is how you write the paper (complete sentences, proper grammar, following personal preferences, work cited page, and all that basic stuff and beyond).