Question

plasma membranes are selectively permeable, or semipermeable, meaning that
○ the membrane allows substances to enter the cell, but not to exit.
○ the membrane permits the transport of only certain substances.
○ the membrane allows osmosis, but not movement of solutes, into or out of the cell.
○ the membrane allows substances to pass through freely.

Explanation:

Selective permeability (or semipermeability) of plasma membranes means they regulate which substances can cross, allowing only specific ones (based on size, charge, etc.) to pass through, while restricting others. This is a core property of cell membranes for maintaining cellular homeostasis.

Answer:

the membrane permits the transport of only certain substances.