Final answer:
The salinity, temperature, and density of sea water are interconnected. The temperature and salinity of sea water determine its density. The amount of salt in sea water determines the temperature at which it freezes.
Step-by-step explanation:
The salinity, temperature, and density of sea water are interconnected. One piece of evidence supporting this conclusion is that the temperature and salinity of the sea water determine its density, as stated in the text.
Another piece of evidence is the distinct decrease in salinity near the equator and at both poles, which is due to different reasons. Additionally, the text mentions that the amount of salt in sea water also determines the temperature at which it freezes.