OSMT (Ontario Society of Medical Technologists) Practice Exam

The plasma membrane in an animal cell is indeed often referred to as the cell membrane, which is a crucial structure that separates the internal environment of the cell from the outside. It plays a key role in maintaining the cell's integrity and regulating what enters and leaves the cell.

Furthermore, the plasma membrane is semi-permeable, meaning it selectively allows certain substances to pass while blocking others. This characteristic is essential for maintaining homeostasis within the cell by controlling the movement of ions, nutrients, and waste products.

Additionally, the membrane is considered selective, as it can actively transport specific molecules through embedded proteins, responding to the cell's needs and changes in the external environment.

Together, these properties—being the cell membrane, semi-permeable, and selective—are fundamental characteristics of the plasma membrane, making the comprehensive answer "All of the above" the most accurate choice.