Final answer:
Salinity and density are directly proportional, where an increase in salinity leads to an increase in density, particularly noticeable in experiments involving the addition of salt to water.
Step-by-step explanation:
In the context of the salinity-density experiment results summarized, the correct statement would be that salinity and density are directly proportional. This means as salinity increases, the density of the solution also increases. This relationship can be observed through different experiments where by increasing the salinity of water, for instance by adding salt, the density of the mixture rises correspondingly.
Understanding the direct relationship between mass and density for blocks of the same volume is also crucial in physics. If two blocks have the same volume but different masses, the one with the greater mass will have a higher density. This is explored further in activities using density simulations which illustrate how the density of the object affects its interaction with fluids of different densities.