Final answer:
If alveolar ventilation is low, the body increases respiratory rate while decreasing volume per breath; if high, it decreases respiratory rate and may increase volume per breath. The correct answer is option (d).
Step-by-step explanation:
When considering how the respiratory rate and volume of air per breath will change if alveolar ventilation is too high or too low, we must understand the body's need to maintain a stable level of carbon dioxide and oxygen. If alveolar ventilation is too low, the body will attempt to compensate by increasing the respiratory rate to prevent carbon dioxide buildup, while the volume of air per breath (tidal volume) may decrease as the breathing becomes quicker and shallower. Conversely, if alveolar ventilation is too high, the body will reduce the respiratory rate to retain more carbon dioxide, hence decreasing the number of breaths per minute, while potentially increasing the volume of air per breath to ensure each breath is more effective.Therefore, the correct answer to the question of how the respiratory rate and volume of air per breath will change if alveolar ventilation is too high or too low is option (d): Decrease in both respiratory rate and air volume if ventilation is high, and increase in respiratory rate and decrease in volume of air per breath if ventilation is low.
If alveolar ventilation is too high, the respiratory rate will increase while the volume of air per breath decreases. This is because when ventilation is high, the body needs to exhale more frequently to remove excess carbon dioxide from the lungs. However, the volume of air per breath decreases to maintain the balance. On the other hand, if alveolar ventilation is too low, the respiratory rate will decrease while the volume of air per breath increases. In this case, the body needs to take deeper breaths to compensate for the reduced air flow, resulting in an increased volume of air per breath.