Complete each of the. following sentences by choosing the correct term from the word bank.
loudness, echoes, pitch, noise, solids, sound quality, vibrations, wavelength frequency, wave, vacuum, amplitude, lesser, infrasonics, ultrasonics
Sound is produced by ________ .

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks us to complete the sentence "Sound is produced by ________." We need to choose the correct term from the provided word bank.

2. **Analyzing the Word Bank:** The word bank includes the following terms: loudness, echoes, pitch, noise, solids, sound quality, vibrations, wavelength, frequency, wave, vacuum, amplitude, lesser, infrasonics, ultrasonics.

3. **Identifying the Correct Term:** To determine what sound is produced by, we need to think about the nature of sound. Sound is a mechanical wave that travels through a medium, and it is created when an object vibrates.

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