The total air capacity of lung is

Question

Accepted Answer

The correct option is (3):
The figure 4.5-5 litre represents a common range cited for the Total Lung Capacity (TLC) in the context of general physiological measurements, particularly as a slightly conservative average that encompasses the typical capacity for both men and women. Total Lung Capacity is the maximum volume of air that the lungs can hold after a maximal inspiration. The actual physiological average for a healthy adult male is closer to 6 litres, while for a female, it averages around 4.2 litres. Therefore, 4.5-5 litres is the most representative and contextually correct option among the choices, effectively capturing a midpoint of the healthy adult range and representing the vital capacity for many individuals, which is a major component of TLC.

The incorrect option is (1):
The range of 2-3 litres is physiologically far too low to represent the total air capacity of healthy adult lungs. This smaller volume is approximately equal to the *Inspiratory Capacity* or perhaps the sum of the *Tidal Volume* (the air inhaled/exhaled during normal breathing) and the *Inspiratory Reserve Volume* (the extra air that can be forcibly inhaled). To be considered the *Total Lung Capacity*, the measurement must also include the *Residual Volume* (the air that always remains in the lungs after a maximal exhalation to keep them from collapsing), which would push the total capacity significantly beyond 3 litres.

The incorrect option is (2):
While 6 litres is the accepted average Total Lung Capacity (TLC) for a healthy young male, the upper limit of 8 litres is considered an exceptionally high capacity. This volume is typically only recorded in very tall or large individuals, or highly trained endurance athletes like marathon runners and swimmers. As the question asks for the general total air capacity and not a maximum capacity for elite athletes, the range of 6-8 litres overshoots the typical, standard value expected for the general population in an examination context.

The incorrect option is (4):
The claim that "All options are wrong" is incorrect because Option 3, which states 4.5-5 litre, provides a recognized and plausible value within the range of adult human lung capacity. Since 4.5-5 litres is a common reference for Vital Capacity and is very close to the overall Total Lung Capacity of an average person, it is the designated correct answer. Consequently, a correct choice exists among the options provided, making this option invalid.