Final answer:
Gas exchange surfaces in the lungs are characterized by a large surface area, decreased membrane thickness, and the presence of surfactant, making options A, C, and D correct (F).
Step-by-step explanation:
The characteristics that apply to gas exchange surfaces in the lungs include a large surface area, decreased membrane thickness, and the presence of surfactant. Specifically, the lungs contain approximately 300 million alveoli, providing a significant surface area for efficient gas exchange.
This vast surface area, roughly equivalent to a tennis court, dramatically increases the amount of gas that can be diffused into and out of the lungs. Additionally, the respiratory membrane is made up of alveolar and capillary walls that are each only one cell thick, reducing the distance over which gases like O₂ and CO₂ must diffuse. The presence of a surfactant reduces the surface tension within the alveoli, preventing their collapse and ensuring that the large surface area is maintained for gas exchange. Multiple cell layers would impede gas exchange and are not a characteristic of the alveolar-capillary interface. Therefore, the correct answer to which characteristics apply to gas exchange surfaces in the lungs is F: A, C, and D are correct.