The answer to this is surface wave i think
The lighter components are able to rise higher in the column before they are cooled to their condensing temperature, allowing them to be removed at slightly higher levels.
I hope this helps
The answer to the question is D.
Ocean water freezes at a lower temperature than freshwater. ... Fresh water freezes at 32 degrees Fahrenheit but seawater freezes at about 28.4 degrees Fahrenheit , because of the salt in it.