How does osmosis differ from diffusion?

Osmosis is specifically defined as the movement of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process is crucial for maintaining the balance of fluids in cells and is a special case of diffusion, but it is characterized by its focus on water rather than any solute.

In contrast, diffusion generally refers to the movement of particles from an area of higher concentration to an area of lower concentration, which can apply to gases, liquids, and solids. Therefore, choice B accurately captures the essential nature of osmosis, highlighting its unique role in water transport across membranes, which is fundamentally important in biological systems for processes like nutrient absorption and waste removal.

Understanding osmosis is vital because it illustrates how organisms regulate their internal environments and maintain homeostasis through the movement of water, impacting cellular functions and overall health.