Functional residual capacity is?

the volume of air inhaled during inspiration

the volume of air exhaled during exhalation

the maximal amount of air the can be exhaled after quiet expiration

the amount of air left in the lungs at the end of normal resting expiration

the volume of air expired forcefully after maximar inspiration

Functional residual capacity (FRC), is the volume remaining in the lungs after a normal, passive exhalation.

It is the combination of residual volume (RV) and the expiratory reserve volume

In a normal individual, this is about 3L.

The FRC also represents the point of the breathing cycle

where the lung tissue elastic recoil and chest wall outward expansion are balanced and equal.