One of the characteristics of ocean water that causes ocean
currents is salinity. Differences in salinity can generate
movement in the ocean because the amount of dissolved salt in ocean water correlated to—?

Differences in salinity can generate  movement in the ocean because the amount of dissolved salt in ocean water correlated to heat or temperature.

Explanation:

When the molecules of water in ocean heat up they get expanded. This expansion creates additional storage where salt and other substances like calcium can fit into. Therefore, as warmer water will contain more salt and other particles than cold water; it may have a greater salinity. The greater the salinity of salt water, the more concentrated it is, in order to link that to ocean currents.

The water will settle when the salinity is heavy enough, causing a current in convection. This implies that cold water can lay on top of warm water if warm water has adequate salinity, so that the normal movement of a current can actually be inverted depending on the ocean water's associated density, salinity and temperature.

the endomembrane system i think