Final answer:
Semipermeable membranes allow the flow of solvent molecules and prevent the flow of solute particles. In biological processes such as osmosis, solvent moves through the membrane to balance solute concentration.
Step-by-step explanation:
Semipermeable membranes are critical in various biological processes, including osmosis, which is the movement of solvent molecules through a membrane. A semipermeable membrane allows the flow of solvent, such as water, while preventing the flow of solute particles, maintaining selective permeation based on molecule size, shape, polarity, and charge. For instance, in the human body, cell membranes are semipermeable, allowing solvent and certain small molecules to pass through while blocking others, similarly to how dialysis membranes work.
In lay terms, a semipermeable membrane acts somewhat like a filter; it lets specific substances pass while blocking others. In the context of osmosis, the diffusion-driven transfer of solvent molecules often occurs from a region of lower solute concentration to a region of higher concentration, aiming to equalize the solute concentrations on both sides of the membrane. As such, for the question posed, the answer is: Semipermeable membranes let solvent flow through it.