How does a cell maintain homeostasis both within itself and as part of a multicellular organism?

Cells maintain homeostasis through the cell membrane which regulates what comes in and out of the cell. For example, if there is too much water in a cell, the cell membrane will allow for the excess water to come out. The chemicals and items released from the cells help maintain the multicellular's homeostasis overall. Also since the cells are part of the organism, all of them must maintain homeostasis or the organism will die.