Final answer:
It is true that the cell membrane's primary role is to maintain the cell's internal conditions by controlling molecule movement across it, ensuring homeostasis through selective permeability.
Step-by-step explanation:
True, one of the most important functions of the cell membrane is to keep the cell's internal conditions relatively constant by regulating the movement of molecules from one side of the membrane to the other. The cell membrane is defined as selectively permeable, meaning it allows certain materials to freely enter or leave the cell while restricting others. This selective permeability is crucial for maintaining homeostasis, which is essential for the cell's survival and function. Through membrane transport mechanisms involving passive and active transport, cells can control the influx and efflux of substances necessary for their operation.