Division of mammalian lungs into a very large number of tiny alveoli around alveolar ducts opening into brondchioles, is

Options

A. An inefficent system of ventilation of alveloi through with very little residual sir
B. An inefficent system of ventilating the alveoli resulting in very high percentage of residual air in the lungs
C. A very efficent system of ventilating the alveoli with no residual air
D. An efficient system of ventilation of alveoli with little or no residual air

Answer

d