Concept:Isohalines are lines drawn on a map connecting points with equal salinity in water bodies.Explanation:The prefix “iso-” means equal, and “haline” refers to salt content.These lines are used in oceanography to show the distribution of salinity across oceans.Common isopleths include: isotherms (temperature), isobars (pressure), isohyets (rainfall), and isohalines (salinity).Therefore, isohalines specifically represent equal salinity.Answer:Salinity.