Question

The human lung has about 80 million alveoli. Give two features of the alveoli that allow large amounts of oxygen to enter the blood.

Answer 1

Answer:

Alveoli forms the respiratory surface in human body.Each alveolus is sac like structure bounded by a single layer of epithelial cells.It is bound on the outside by a network of capillaries. The pulmonary artery from the heart containing deoxygenated blood enters the lungs and then becomes oxygenated after passing in the capillaries through the lungs.