42.A cell increases in volume if the external medium is A. Hypotonic B. Hypertonic C. Isotonic D. None of the above
Option A. Osmosis is defined as the movement of solvent molecules from a region of their higher concentration (more dilute solution) to a region of their lower concentration (more concentrated solution), through a semipermeable membrane. Hence, the water molecules move into a cell when a cell is placed in a hypotonic medium (resulting in an increase in cell volume) and water moves out of the cell when a cell is placed in a hypertonic medium (resulting in a decrease in cell volume).
