Cytoskeletal filaments are structures which allow movement. In cilia and flagella, the cytoskeletal filaments are present in the form of microtubules and the primary work of these structures is to facilitate in movement.
Cilia is also present in mammals to facilitate the movement of fluids in cells.
Structurally, there is no difference between cilia and flagella. The only difference between cilia and flagella is in their lengths.
Explanation: Elodea or Paramecium live in fresh-water lakes and they are not adaptive to salt-water. Oceans are salty and the cells will lose water due to osmosis and eventually dry up and fall apart.