What might happen if you shift to a low gear while travelling at a high speed?

Your answer is correct. Shifting to a low gear at high speed can cause the rear wheel to lock because the engine braking is suddenly very strong, making the rear wheel lose grip. This loss of control increases the risk of crashing. However, it does not cause the front wheel to lift off the ground; that usually happens when accelerating hard, not when downshifting. Remember, always match your speed to your gear to avoid locking the rear wheel, especially on motorcycles. This helps you stay safe and maintain control.