Answer:
c - the volume of solution changes due to movement of water.
Explanation:
Passive transport is the movement of a substance from an area of high concentration to a low concentration across a semi-permeable membrane, that occurs without the expenditure of energy.
Option A is true: substances will always move from an area of high concentration to a lower concentration. This creates what is called a concentration gradient (which forms when a physical area contains a range of concentrations of s particular substance (option D). This occurs until the concentration of a solution approaches an equilibrium, as indicated in option B.
However, the movement of substances does not affect the movement of or the volume of water, only the chemicals, ions etc. in the water.
