What is the primary function of the ventral respiratory group during exercise?

The primary function of the ventral respiratory group (VRG) during exercise is to activate active expiration. During physical activity, the body increases its demand for oxygen and needs to expel carbon dioxide at a higher rate. The VRG is responsible for the rhythm of breathing and coordinates the muscles involved in active expiration, such as the abdominal muscles and internal intercostals. This activation allows for a quicker and more forceful exhalation, which is essential for managing the respiratory demands during exercise.

In contrast, the other options do not accurately reflect the role of the VRG during exertion. Passive breathing is regulated more by the automatic processes controlled by the medulla oblongata rather than by the VRG during periods of high activity. While stabilizing the diaphragm is crucial for respiration, the action of stabilizing does not directly relate to what the VRG primarily does during exercise. Promoting deep inhalation is more closely associated with the action of the dorsal respiratory group, which focuses on inhalation rather than the active expiration managed by the VRG.