Which features are typical of an effective gas exchange system?

• A. Cell wall
• B. Ribosomes
• C. Large surface area to volume ratio and good ventilation and rich blood supply
• D. Glycogen

Answer: (C)

Gas exchange works best when there is a large surface area relative to volume, continuous movement of air or water to maintain diffusion gradients, and a rich blood supply to transport gases away and keep the gradient favorable. A large surface area to volume ratio provides more space for molecules to diffuse; good ventilation keeps fresh gas on one side and maintains a steep partial pressure difference; and a dense blood supply ensures rapid uptake of oxygen and removal of carbon dioxide, sustaining the gradient that drives diffusion.

A cell wall is a structural feature of plant and some microbial cells, not a factor that enhances gas exchange efficiency. Ribosomes are involved in protein synthesis, not gas diffusion. Glycogen is an energy storage molecule, unrelated to how effectively gases diffuse across a exchange surface.