Assertion (A): The partial pressure of oxygen (pO2) in atmospheric air is higher than the pO2 in alveolar air.
Reason (R): The incoming atmospheric air mixes with the residual air already present in the lungs, which is rich in CO2 and poor in O2.
Assertion (A): The partial pressure of oxygen (pO2) in atmospheric air is higher than the pO2 in alveolar air.
Reason (R): The incoming atmospheric air mixes with the residual air already present in the lungs, which is rich in CO2 and poor in O2.