The annual health-care costs for people who are extremely obese are almost twice those of normal-weight people. Very sobering is the fact that severe obesity is increasing at a much faster rate than moderate obesity, quadrupling from 1986â2000.6.
As a sea is connected to the oceans, which are salt water, most seas are also salt water. This is not a distinguishing feature between a sea and a lake, however, as lakes are more commonly freshwater but can be salty depending on their source and their surroundings.
Since salt ions are heavier than water molecules, seawater is denser than freshwater. The density of seawater ranges from 1020 to 1030 kg/m 3 while the density of freshwater is about 1000 kg/m 3. Variations in salinity also cause the freezing point of seawater to be somewhat lower than that of freshwater.