Alexis and candace were testing different surfaces to see which one had the least friction. they predicted that the marble, seen above, would travel fastest down the ramp when the surface covering had the least friction. alexis and candace used rocks, plywood, and velcro to cover the ramp. they let the marble go, not pushing it, but letting gravity pull the marble to the bottom of the ramp. which of these is the hypothesis for the experiment? a) rocks and velcro do not make very good ramp coverings. b) changing the size of the marble will affect its speed. c) the height of the ramp will determine the speed of the marble. d) the marble will travel fastest down the ramp with the least friction.