Question

question 2 membranes that allow some molecules, such as oxygen and water, to move freely across. selectively permeable equilibrium isotonic gradient membranes

Explanation:

Selectively permeable membranes allow certain molecules like oxygen and water to pass through while restricting others. Equilibrium refers to a state of balance, isotonic relates to solutions with equal solute - solvent ratios, and gradient membranes are not the correct term for this property.

Answer:

A. selectively permeable