Movement of solvent molecule from a region of its higher concentration to a region of its lower concentration through a semi- permeable membrane is refferred to as

Options

A. simple diffusion
B. facilitated diffusion
C. osmosis
D. active transport.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the movement of solvent molecules from an area of higher concentration to an area of lower concentration through a semi-permeable membrane.

2. **Defining Key Terms**:
- **Solvent Molecules**: These are substances that dissolve solutes; in biological contexts, this is often water.
- **Semi-permeable Membrane**: A barrier that allows certain substances to pass through while blocking others.

3. **Identifying the Process**: The movement described in the question is a passive process where solvent molecules move down their concentration gradient (from high to low concentration).

4. **Differentiating Between Processes**:
- **Simple Diffusion**: Movement of solutes from high to low concentration without a membrane.
- **Facilitated Diffusion**: Movement of solutes through a membrane with the help of carrier proteins.
- **Active Transport**: Movement of molecules against their concentration gradient, requiring energy (ATP).
- **Osmosis**: Specifically refers to the movement of water (solvent) across a semi-permeable membrane from an area of higher water concentration (or lower solute concentration) to an area of lower water concentration (or higher solute concentration).

5. **Conclusion**: Given the context of the question, the correct answer is that the movement of solvent molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane is referred to as **osmosis**.

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