Ventilation perfusion ratio is maximum at -

Ans. is 'a' i.e., Apex of lung o Due to gravity, the apical alveoli are both underventilated and underperfused while the basal alveoli are both overventilated and overperfused.o However, gravity affects perfusion much more than it affects ventilation.o Hence, apical alveoli are more underperfused than underventilated while the basal alveoli are more overperfused than overventilated.o Therefore, V/Q is maximun at apex (about 3.0) and least at base (about 0.6).