Question

our respiratory structures are designed to promote the passive movement of gases across membranes through the process of
osmosis
bulk flow
facilitated transport
diffusion

Explanation:

• Osmosis is the movement of water molecules across a semi - permeable membrane.
• Bulk flow is the movement of fluids due to pressure differences.
• Facilitated transport requires a transport protein.
• Diffusion is the passive movement of gases (or other substances) from an area of higher concentration to an area of lower concentration across a membrane. In the respiratory system, oxygen diffuses from the alveoli (high concentration) into the blood (low concentration) and carbon dioxide diffuses from the blood (high concentration) into the alveoli (low concentration).

Answer:

diffusion