The neck and abdominal muscles are involved in a:

A. The cerebral cortex is involved in higher brain functions like thinking and voluntary control of breathing but does not contain central chemoreceptors.
B. Central chemoreceptors are located in the medulla oblongata, a part of the brain stem. They detect changes in the pH of cerebrospinal fluid, which reflects CO₂ levels in the blood, and help regulate breathing accordingly.
C. The aorta contains peripheral chemoreceptors, not central ones. These aortic bodies monitor blood oxygen, carbon dioxide, and pH, but they are outside the central nervous system.
D. The cerebellum coordinates motor control and balance and does not play a role in chemoreception.

A. Quiet inspiration involves the diaphragm and external intercostal muscles without significant involvement of the neck and abdominal muscles.
B. Forceful exhalation (such as during coughing or strenuous activities) engages the abdominal muscles and sometimes the neck muscles (such as the sternocleidomastoid), as they help to push air out of the lungs by increasing intra-abdominal and intrathoracic pressure.
C. None of the answers are correct is incorrect because forceful exhalation involves these muscles.
D. Quiet exhalation primarily relies on passive recoil of the lungs and relaxation of the diaphragm, with minimal involvement of the neck or abdominal muscles.