Which of the following factors does not affect the salinity of the oceans?

The shape of the ocean floor does not affect the salinity of the oceans. The salinity of seawater is primarily influenced by the amount of dissolved salts in it. The ocean floor, on the other hand, refers to the physical features of the seafloor, including the depth, slope, and shape of the ocean basins. While the shape of the ocean floor can affect ocean currents and their mixing patterns, it does not directly affect the amount of salt in seawater. The other factors listed, such as the rate of evaporation, the degree of water mixing by currents, and the amount of fresh water added by rain, all have a direct impact on the salinity of the oceans.