Question

the respiratory membrane consists of:
o pulmonary capillary bed
o walls of alveoli and capillaries
o walls of bronchioles and alveoli
o walls of alveoli and mucous membrane

Explanation:

The respiratory membrane is where gas - exchange occurs in the lungs. It is composed of the walls of alveoli and capillaries which allows for the diffusion of oxygen and carbon - dioxide.

Answer:

walls of alveoli and capillaries