Which best describes the permeability of a membrane?

O

A. The number of molecules in the membrane

O

B. The total thickness of the membrane

O

C. The flexibility of the membrane

O

D. The ability to allow materials to cross a membrane

D. The ability to allow materials to cross a membrane

Explanation:

It all has to do with the size of the materials trying to pass through. All other options do not make sense. Thickness, flexibility, and amount of molecules do not describe permeability.