@kaykay101,
I had virtually the same assignment fifteen years ago. I argued in favor of allowing bicycles on wilderness trails, and disallowing horses. I think I got extra points from my backpacking instructor by calling it "View from the Shanks Mare".
Like ossobuco said, pick something you are interested in, with opinions already formed. Be fair, and show points from both sides - you never know what prejudices your instructor may have on the subject.