Questions: Which term refers to the diffusion of water through a semipermeable membrane?

The answer is the fourth one (or D): Osmosis.

Explanation for each option:

1. Facilitated diffusion: This is the process of spontaneous passive transport of molecules or ions across a biological membrane via specific transmembrane integral proteins. It does not specifically refer to the movement of water.

2. Diffusion: This is the general process by which molecules spread from areas of high concentration to areas of low concentration. While diffusion can involve water, it does not specifically refer to the movement of water through a semipermeable membrane.

3. Active transport: This is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration, against the concentration gradient, and requires energy. It does not specifically refer to the movement of water.

4. Osmosis: This is the process by which water molecules move through a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. This term specifically refers to the diffusion of water.

5. Endocytosis: This is the process by which cells engulf external substances, bringing them into the cell. It does not specifically refer to the movement of water through a semipermeable membrane.

Summary: The term that refers to the diffusion of water through a semipermeable membrane is "Osmosis."