Desalination of sea water is based on the phenomenon.............

Explanation

**Step-by-Step Solution:**

1. **Understanding Desalination**: Desalination is the process of removing salt and other impurities from seawater to produce fresh water. This is crucial for providing drinking water in areas where freshwater resources are scarce.

2. **Identifying the Process**: The primary method used for desalination is reverse osmosis. It is important to understand what osmosis is before we can grasp reverse osmosis.

3. **Defining Osmosis**: Osmosis is the movement of solvent molecules (usually water) through a semi-permeable membrane from a region of lower solute concentration (more water) to a region of higher solute concentration (less water).

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