semipermeable impervious resilient unyielding
I gave my students this multiple choice question: Cell membranes allow some molecules to move freely across the membrane, while other molecules are restricted. Which term best describes this capability of a cell membrane?

Only one answer is correct among these 4 choices:
- semipermeable
- impervious
- resilient
- unyielding

Could you tell me which one is correct?

semipermeable