Final answer:
The normal tidal volume in an average 70 kg adult is approximately 500 mL, which is the amount of air inhaled and exhaled during a normal breath, whereas the total lung capacity can reach up to six liters.
Step-by-step explanation:
The normal tidal volume in an average 70 kg adult is approximately 500 milliliters (mL). This volume represents the amount of air that is inspired and expired during a single, normal breath without exertion. This is contrasted with other lung volume measurements such as the residual volume, which is the amount of air left in the lungs after a forceful exhalation, and inspiratory capacity, which is the maximum amount of air an individual can take in during a deep breath from the position of normal expiration.
Total lung capacity (TLC) is the sum of the residual volume, expiratory reserve volume, tidal volume (TV), and inspiratory reserve volume, which in an average adult male can total up to six liters. However, the tidal volume only accounts for a fraction of this capacity. The correct answer to the student's question is therefore option D) 500.