The breathing process is primarily controlled by:
- The diaphragm - It is the main muscle involved in breathing, contracting to allow air to enter the lungs.
- Rib muscles (intercostal muscles) - These muscles assist in expanding and contracting the rib cage during breathing.
While the pharynx plays a role in the respiratory pathway and blood vessels are involved in gas exchange and regulation of breathing, they are not among the primary controllers of the breathing process. Therefore, the correct answers are the diaphragm and rib muscles.