Explanation: A sawtooth wave is uniquely characterized by a linear, gradual change in one direction (the ramp) followed by a very swift, near-instantaneous return to its starting level (the retrace), or vice versa. This inherent asymmetry directly means its rise time will be significantly different from its fall time, or vice versa. In contrast: * **Sine and Cosine waves** are smooth, continuous, and inherently symmetrical waveforms. Their rise and fall characteristics are balanced. * **Square waves** are characterized by rapid, almost instantaneous transitions between two voltage levels. Ideally, the rise time and fall time of a square wave are equally short and symmetrical, not significantly different from each other. Therefore, the sawtooth wave is the only waveform described that exhibits this specific asymmetrical rise/fall characteristic.