Final answer:
Mammalian red blood cells are used in the study of the plasma membrane because their membranes can be isolated without the risk of contamination. This allows for a focused examination of the properties and functions of the plasma membrane.
Step-by-step explanation:
The primary reason that mammalian red blood cells are used in the study of the plasma membrane is because their membranes can be isolated without the risk of contamination from other types of membranes.
Red blood cells have no nucleus or other organelles, so they have only a plasma membrane. This makes them a good source for studying the properties and functions of the plasma membrane in isolation.