Final answer:
Vital capacity (VC) is the sum of tidal volume (VT), inspiratory reserve volume (IRV), and expiratory reserve volume (ERV), and does not include residual volume (RV). It is used to assess a person's respiratory health.
Step-by-step explanation:
Vital capacity (VC) is defined as the maximum amount of air a person can expel from their lungs after a maximum inhalation. It can be calculated as the sum of the tidal volume (VT), expiratory reserve volume (ERV), and inspiratory reserve volume (IRV). Therefore, the correct formula for vital capacity is VC = VT + IRV + ERV, which excludes the residual volume (RV) as it cannot be expelled from the lungs. Understanding vital capacity is a significant part of assessing respiratory health, as it reflects the total volume of air that participates in gas exchange.