Explanation: osmosis is the movement of the water molecules from a region of high concentration of solute to a region of low concentration of solute, through a semi-permeable membrane.
This movement occurs until the concentration on both sides is on equilibrium.
Semi permeable membrane allows the movement of water only but not the solute.
In this case,water moves from region A to region B.
Fish are aquatic vertebrates with gills, appendages, if present, in the form of fins, and usually a skin with scales of dermal origin. They are the most ancient and most diverse of clad vertebrata