* Cell membranes are essential structures found in all living cells, including those of protists and fungi. They act as a barrier between the cell's internal environment and the external environment.

* Protists are a diverse group of eukaryotic organisms that are not classified as animals, plants, or fungi. They have cell membranes made up of a phospholipid bilayer, just like other eukaryotic cells.

* Fungi are also eukaryotic organisms that have cell membranes composed of a phospholipid bilayer.

Therefore, both protists and fungi possess cell membranes.