The process of boiling seawater in order to separate it into freshwater vapor and brine is usually defined as __________.

Correct Answer: Option D — evaporation

Evaporation is the fundamental thermodynamic process in marine distillation where seawater is heated until it undergoes a phase change into vapor. This separation leaves behind dissolved solids and impurities, known as brine, allowing the pure water vapor to be subsequently condensed into fresh water.