Answer:
Vital capacity can be defined as the maximum volume of air a person can breathe in after a forced expiration. It is equivalent to the sum of expiratory reserve volume (ERV), tidal volume (TV) and inspiratory reserve volume (IRV).
- Expiratory reserve volume (ERV): It refers to the volume of air a person can exhale by forcible expiration or air exhaled from the end-expiratory position.
- Tidal volume (TV): It is a volume of air inhaled or exhaled during a normal respiration.
- Inspiratory reserve volume (IRV): Maximum volume of air a person can inhale from the end-respiratory position.
Now, the vital capacity of John would be = 450 + 2600 + 900 ml
= 3950 ml or 3.95 L.
