Final answer:
To modify pitch, change the frequency of a sound wave. To modify intensity, change the amplitude of a sound wave.
Step-by-step explanation:
The perception of pitch is related to the perception of frequency, while the perception of intensity is related to the perception of loudness. To modify pitch, you can change the frequency of a sound wave. For example, if you pluck a guitar string closer to the bridge, it produces a higher pitch compared to plucking it closer to the neck. To modify intensity, you can change the amplitude of a sound wave. Increasing the amplitude makes the sound louder, while decreasing the amplitude makes it softer. For example, speaking with a louder voice increases the intensity of the sound.