Concept:Maps use special lines to join points sharing the same value of weather elements.Explanation:The term "isotherm" comes from "iso" meaning equal and "therm" meaning heat or temperature.Thus, an isotherm is a line drawn on a map passing through places that record the same temperature above sea level.Other lines represent different elements: isohyets show equal rainfall, isobars show equal pressure, and isohalines show equal salinity.Since the question specifically asks about temperature, the correct term is isotherm.Answer:A. isotherms