Diffusion is defined as the movement of molecules from a high concentration to a low concentration.

Diffusion is defined as the movement of molecules from a high concentration to a low concentration.

• A. Movement of Water Across A Selectively Permeable Membrane
• B. Movement of Molecules From A High Concentration To A Low Concentration
• C. Movement Of Molecules Against A Concentration Gradient Using Energy
• D. Movement Of Solutes Into Vesicles

Answer: (B)

Diffusion is about particles moving down their concentration gradient due to random molecular motion, and it is a passive process that does not require energy. The statement that diffusion involves movement of molecules from a high concentration to a low concentration captures this directional flow down the gradient, which is the hallmark of diffusion. This applies to solutes that can move through the medium or membranes without expending cellular energy, until equilibrium is reached where there’s no net movement. It’s helpful to recognize related ideas briefly: moving water across a selectively permeable membrane is osmosis, a specific case of diffusion for water, driven by water potential rather than solute concentration alone. Moving substances against a gradient using energy describes active transport, and moving large amounts of material into or out of the cell via vesicles describes vesicular transport.

Diffusion is about particles moving down their concentration gradient due to random molecular motion, and it is a passive process that does not require energy. The statement that diffusion involves movement of molecules from a high concentration to a low concentration captures this directional flow down the gradient, which is the hallmark of diffusion. This applies to solutes that can move through the medium or membranes without expending cellular energy, until equilibrium is reached where there’s no net movement.

It’s helpful to recognize related ideas briefly: moving water across a selectively permeable membrane is osmosis, a specific case of diffusion for water, driven by water potential rather than solute concentration alone. Moving substances against a gradient using energy describes active transport, and moving large amounts of material into or out of the cell via vesicles describes vesicular transport.