In which direction is the net movement of water molecules?

The net movement of water molecules occurs in response to differences in water concentration or osmotic gradients across a semi-permeable membrane. This movement typically happens from an area of higher water concentration to an area of lower water concentration, or from an area of lower solute concentration to an area of higher solute concentration.

This movement of water across a semi-permeable membrane is known as osmosis. Water moves passively through the membrane to equalize the concentration of solutes on both sides. It continues until the concentration gradient of water (or osmotic pressure) is balanced between the two sides.

Therefore, the net movement of water molecules is from an area of lower solute concentration (or higher water concentration) to an area of higher solute concentration (or lower water concentration), across the semi-permeable membrane.