Final answer:
The plasma membrane is selectively permeable, allows cell-to-cell interaction, and encloses the cell's contents.
Step-by-step explanation:
The plasma membrane is selectively permeable and allows certain substances to enter or leave the cell while preventing others from crossing. It also acts as a site of cell-to-cell interaction and recognition, enabling tissue and organ formation and playing a role in the immune response. Additionally, the plasma membrane encloses the contents of the cell, defining its borders and protecting its internal structures.