Simple Diffusion as Passive Transport

Steps:

• Recall that simple diffusion is the net movement of molecules from high to low concentration without energy input.
• Evaluate option A: Diffusion does not need specific membrane molecules; it's facilitated by the lipid bilayer's properties.
• Evaluate option B: It matches the definition of passive transport, requiring no cellular energy.
• Evaluate options C and D: Diffusion occurs in various contexts beyond membranes or specific cell types.

Why B is correct:

• Simple diffusion follows Fick's law of diffusion, moving substances passively down their concentration gradient without ATP or carrier proteins.

Why the others are wrong:

• A: Simple diffusion is non-specific and does not require channel or carrier proteins in the membrane.
• C: Diffusion can occur through gases, liquids, or across membranes but does not always need a membrane.
• D: Simple diffusion is a physical process occurring in all matter, not limited to prokaryotic or eukaryotic cells.

Final answer: B