Solution: The maximum volume of air a person can breathe in after a forced expiration is known as vital capacity. It is equal to the sum of inspiratory reserve volume (IRV), tidal volume (TV), and expiratory reserve volume (RV). So, the equation is VC = IRV + TV + ERV.

 Significance of Vital Capacity is that-

• It shows how much air may be transformed or regenerated in the respiratory system in a single breath.
• It encourages the act of supplying fresh air and expelling stale air, increasing gaseous exchange between tissues and the environment. As a result, the higher the VC, the more energy is available to the body. A person’s VC provides crucial information for identifying a lung disease.
• The additional amount of oxygen accessible for glucose oxidation is represented by the excess amount of inhaled air. More energy is available to the body in this manner.