Flagella are long, thin, hair-like structures that project from the cell surface. They are used for locomotion, allowing cells to move through fluids.
Some examples of cells with flagella include:
* Sperm cells: Their flagella propel them towards the egg.
* Some bacteria: Flagella help them move towards food or away from harmful substances.
* Protists: Flagella enable these single-celled organisms to swim.
