A unicellular organism has only one cell. This means that the single cell is responsible for all functions, including movement. So, in a unicellular organism, all of the cell functions to move around.

While the entire cell is involved in movement, specific structures within the cell are responsible for locomotion. These can include:

* Flagella: Long, whip-like structures that propel the organism.

* Cilia: Short, hair-like structures that beat rhythmically to create movement.

* Pseudopodia: Temporary extensions of the cytoplasm that allow the organism to "crawl".

Let me know if you have any other questions about unicellular organisms!