Function of cell membrane in short?

The cell membrane, also known as the plasma membrane, serves as a protective barrier that separates the interior of the cell from the external environment. It regulates the movement of substances in and out of the cell, allowing essential nutrients to enter while keeping harmful substances out. Additionally, the membrane facilitates communication and signaling between cells through receptors and proteins embedded within it. Overall, it plays a crucial role in maintaining the cell's homeostasis and integrity.