Which of the following describes the volume of air inhaled and exhaled during a normal breath?

• A. Inspiratory Reserve Volume
• B. Residual Volume
• C. Tidal Volume
• D. Dead Space

Answer: (C)

The amount of air moved in and out with each normal breath is tidal volume. It represents the air exchanged during quiet, resting breathing, typically about 500 mL in an average adult (varying with size and conditioning). Other terms describe different quantities: inspiratory reserve volume is the extra air you can inhale beyond a normal breath; residual volume is the air remaining in the lungs after maximal exhalation; dead space is the portion of each breath that stays in the conducting airways and does not participate in gas exchange. Since the question specifies a normal breath, tidal volume is the best fit.