Question

Which of the following statements accurately describes gas exchange systems in all animals?

• A. Gases are passively transported across the respiratory surfaces
• B. There is counter current exchange of gases across the respiratory surfaces.
• C. All gas exchange systems utilize hemoglobin as a transport protein.
• D. Respiratory surfaces must be moist for diffusion of gases to occur efficiently.
• E. Closed circulatory systems are affiliated with all gas exchange systems.

Answer 1

The correct option is A Gases are passively transported across the respiratory surfaces

The major site of gas exchange are alveoli of lungs. Alveoli are thin, irregular walled and vascularised bag like structure at the end of bronchiole and are the primary sites of exchange of gases.. Oxygen and carbon dioxide are exchanged in these sites by simple diffusion mainly based on pressure or concentration gradient. Hence there is passive transport of gases across the respiratory surfaces.

So, the correct answer is 'Gases are passively transported across the respiratory surfaces'.