I am not sure if this is what you need, but one way that a cell maintains homeostasis is by controlling the movement of substances across the cell membrane. Cells are suspended in a fluid environment, for example, even the cell membrane is fluid. It is made up of a “sea” of lipids in which proteins float. By allowing some materials to enter the cell, but not all, the cell membrane acts almost like a gatekeeper for the cell.
The cell membrane also provides structural support to the cytoplasm, recognizes foreign material, and communicates with other cells, all of which contribute to maintaining homeostasis.