Which of the following systems includes the abdominal muscles involved in breathing?

The respiratory system is the correct choice because it encompasses the anatomical structures and muscles involved in the process of breathing, including the abdominal muscles. Breathing is a crucial component of respiration, which not only supplies oxygen to the body but also plays a vital role in vocalization and speech production.

The abdominal muscles assist in forced exhalation by contracting and pushing the diaphragm upward, thereby facilitating the expulsion of air from the lungs. This action is particularly important during speech when a controlled airflow is required for the production of sound.

In contrast, the supralaryngeal system focuses on structures above the larynx, such as the vocal tract and articulators, which are more involved in shaping sounds rather than in the mechanics of breathing. The phonatory system pertains to the voice production mechanisms within the larynx, and while it is involved in voiced sounds, it does not directly address the respiratory mechanics associated with abdominal muscles. The auditory system is entirely related to hearing and sound processing, having no role in the mechanics of breathing.