Which structure is also known as the voice box?

The larynx is commonly referred to as the voice box because it plays a crucial role in sound production, which is essential for speaking and vocalization in humans and many animals. The larynx houses the vocal cords (or vocal folds), which vibrate as air passes through them, creating sound. Additionally, the larynx is involved in protecting the trachea against food aspiration and assists in breathing.

In contrast, although the pharynx is closely related to the larynx and serves as part of the throat, it does not have the specific function of sound production. The soft palate is involved in separating the oral cavity from the nasal cavity during swallowing and also plays a role in speech, but it is not where the vocal cords are located. The diaphragm, on the other hand, is a muscle that is essential for respiration but does not produce voice by itself; rather, it aids in airflow to the larynx for sound generation. Thus, the larynx is the correct answer due to its specific function as the anatomical structure responsible for voice production.