Final answer:
Alveolar ventilation remains constant when the respiratory rate decreases and the tidal volume increases, which allows the body to maintain effective gas exchange and meet oxygen demands.
Step-by-step explanation:
Alveolar ventilation remains constant when respiratory rate decreases and tidal volume increases. This balance ensures that the amount of air moved into and out of the alveoli is maintained at a steady level, which is crucial for the effective exchange of oxygen and carbon dioxide.
The work of breathing changes depending on whether the respiratory rate increases with a decrease in tidal volume (resulting in shallow breathing), or the respiratory rate decreases with an increase in tidal volume. These changes help to meet the oxygen demands of the body without altering the overall alveolar ventilation.
Therefore, the correct answer to the student's question is: a) Respiratory rate decreases and tidal volume increases, as both tidal volume and respiratory rate are closely regulated to meet the body's oxygen demands without compromising alveolar ventilation.