Final answer:
When a solute can diffuse through a membrane, equilibrium is reached through the process of osmosis, where water moves to equalize solute concentrations. The correct option is b. equilibrium is reached
Step-by-step explanation:
When a solute is able to diffuse through a membrane, equilibrium is reached. This process is known as osmosis, which is the diffusion of water across a semi-permeable membrane. Water moves from an area of high concentration to one of low concentration, and in osmosis, it moves towards the area of higher solute concentration in an attempt to equalize solute levels on both sides of the membrane.
This will continue until the concentration gradient of water is zero or until osmotic pressure is balanced by hydrostatic pressure. Osmosis is critical in biological systems for maintaining cellular integrity and the balance of solutes and water within and outside the cell. The correct option is b. equilibrium is reached