Reason: <span> In cold regions, changes in salinity alters the water present in ocean. Further, water density also changes with temperature. In general, water density in ocean water increases with decreasing temperature. This is because, when salt is ejected into the ocean as sea ice forms, the water's salinity increases. Since, salt water is heavier, the density of the water increases.</span>
Grinding or breaking an Alka-Seltzer tablet increases the number of particles and increases the surface area. Material which was within the tablet is exposed, allowing for more collisions between reactant particles and resulting in an increased rate of reaction.