Which of the following statements are true of the alveoli and pulmonary capillaries? (Read carefully and select all of the correct statements.)
A)Blood coming into the pulmonary capillaries is low in O2 and high in CO2. B)The alveolar walls are one cell in thickness. C)The total alveoli provide a large surface area for gas exchange. D)The pulmonary capillaries are made of simple squamous epithelium. E)Type II alveolar cells secrete pulmonary surfactant to increase the osmosis of gases. F)Blood leaving the pulmonary capillaries will return to the left atrium of the heart.