Final answer:
The amount of air that can be forcibly inhaled after a normal inspiration is the inspiratory reserve volume (IRV).
Step-by-step explanation:
The amount of air that can be forcibly inhaled after a normal inspiration is the inspiratory reserve volume (IRV). The inspiratory reserve volume is the extra amount of air that can be inhaled beyond a normal breath. It is measured by taking a deep inhalation after a tidal inspiration.