Answer the following question given this paragraph: 

The plasma membrane may have extensions, such as whip-like flagella or brush-like cilia. In single-celled organisms, like those shown in Figure below , the membrane extensions may help the organisms move. In multicellular organisms, the extensions have other functions. For example, the cilia on human lung cells sweep foreign particles and mucus toward the mouth and nose.


Q: In single-celled organisms, plasma membrane extensions, such as whip-like flagella or brush-like cilia, aid in what?

 Choices:

- sensation

- sound

- pressure

- movement

A:
movement
