Which parameter does not change with age?

The choice indicating that functional residual capacity (FRC) does not change with age is accurate because FRC typically remains relatively stable throughout the lifespan, despite various physiological changes that occur as people age.

FRC is defined as the volume of air that remains in the lungs after a normal expiration, and it is a combination of the residual volume and the expiratory reserve volume. As individuals age, while some lung volumes may decrease due to factors like loss of elasticity or respiratory muscle strength, FRC tends to remain consistent. This stability in FRC can be attributed to a balance between the forces that expand the lung and those that contract it; thus, it does not exhibit significant age-related variation.

In contrast, other parameters such as tidal volume, total lung capacity, and expiratory reserve volume do typically change with age. For instance, tidal volume can decrease due to reduced respiratory drive and muscle function. Total lung capacity may decrease as lungs become less compliant, and expiratory reserve volume often diminishes due to increased stiffness of the lungs and a decrease in muscle strength. These age-related changes can impact respiratory efficiency and capacity, leading to a greater reliance on FRC as a stable lung measure throughout life.