Final answer:
In a piece of music, a guitar is likely being referred to, which is a stringed instrument where sound is primarily produced by the vibration of the guitar string. The overtones of wind instruments like a tuba are related to the harmonic series and depend on the structure of the instrument.
Step-by-step explanation:
When referring to the sounds heard in a piece of music, the guitar would be classified as a stringed instrument, the fundamental source of sound within the guitar itself being the vibration of the guitar string. As the string vibrates, it also causes the air inside the guitar (the guitar's resonance chamber) to vibrate, which amplifies the sound. In contrast, the air surrounding the guitar and the ground beneath the musician do not materially produce sound in the context of the guitar playing, but they may affect aspects of the sound's propagation and perception.
Musical overtones, as in the case of wind instruments like the tuba and the bassoon, are additional frequencies that occur above the fundamental frequency and are related to the harmonic series. For a tuba with a fundamental frequency of 32.0 Hz, being closed at one end, its first three overtones would be at frequencies that are odd multiples of the fundamental, so 96.0 Hz (3rd harmonic), 160.0 Hz (5th harmonic), and 224.0 Hz (7th harmonic).