Answer:
See below.
Step-by-step explanation:
You didn't provide a picture or any other real information. And while I usually wouldn't answer questions like that, simply because I couldn't without more info, I think I can give insight to this pretty quickly.
If we're assuming a marble is moving down a ramp in a realistic situation:
-the force of gravity is what makes it go down the ramp to begin with
-the force of friction makes the marble roll and eventually stop
-there may also be air friction acting on the marble, though it wouldn't be very noticeable unless it was going abnormally fast... or down a really, really large ramp I guess