The organisms that have cilia for locomotion.

Explanation

**Step-by-Step Solution:**

1. **Understand Cilia**: Cilia are hair-like appendages found on the surface of certain cells. They are typically numerous and cover the cell's surface.

2. **Function of Cilia**: The primary function of cilia is locomotion, which means they help the organism move. Cilia beat in a coordinated manner, allowing the organism to swim through its environment.

3. **Comparison with Flagella**: Cilia are shorter than flagella, which are another type of appendage that can also aid in movement. While both structures serve similar functions, their size and movement patterns differ.

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