increase friction. carry heavy weights. increase the stopping distance. prevent braking of the bicycle.
I gave my students this multiple choice question: Mountain bike tires have large, knob-like treads. These tires are useful on steep slopes because they

Only one answer is correct among these 4 choices:
- increase friction.
- carry heavy weights.
- increase the stopping distance.
- prevent braking of the bicycle.

Could you tell me which one is correct?

increase friction.