How is osmosis defined?

Osmosis is specifically defined as the movement of water molecules through a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process occurs in response to a concentration gradient, where water will naturally move towards the area of higher solute concentration, effectively diluting it.

This fundamental principle is essential in biological systems, as it regulates the movement of water in and out of cells, maintaining homeostasis and proper cellular function. The semi-permeable membrane allows water molecules to pass while preventing solute particles from doing so, illustrating the selective nature of this process. Understanding osmosis is critical for fields such as biology and chemistry, where the balance of fluids and solutes is vital for sustaining life and carrying out chemical reactions.

The other options do not accurately encapsulate this definition, focusing instead on different processes that aren't specific to osmosis or mistaking the direction of movement regarding solute concentrations.