Simply put, a subject is a broad area of interest. The trouble with a subject is that it is very, VERY broad.When you begin writing a research paper, a subject looms before you like a beautiful, new horizon. You may begin searching for all the books and articles ever written on the subject and trying to read everything you find. That's time-consuming and ultimately frustrating.

Let's say your subject is "mountain climbing." Imagine how many hundred papers could be written on that subject! By narrowing the subject to "amateur mountain climbing on Mt. Everest," for instance, you would save countless hours not having to research every aspect of mountain climbing. You would not have to worry about mountain climbing on Mt. McKinley or Mt. Kilimanjaro or any other mountain in the world! You also would not have to investigate professional mountain climbing--only amateur mountain climbing. That's the choice that Ryan made in narrowing his subject into a more focused topic:

SUBJECT: Mountain climbing TOPIC: Amateur mountain climbing on Mt. Everest

So when you are asked to write an argumentative research paper in one of your college courses (and you are not told what to write about), you need to identify a subject . . . and then begin almost at once focusing your subject into a topic, or narrower aspect of the subject.