The correct answer is option 1, which is isohyets. Isohyets are isolines that connect places with equal amounts of rainfall. They are commonly used in meteorology to represent precipitation patterns on weather maps. Option 2, isotherms, are isolines that join places with equal temperatures. Option 3, isobars, are isolines that connect places with equal atmospheric pressure. Option 4, contours, are isolines that represent the shape and elevation of the land, usually used in topographic maps. It is important to note that each isoline represents a specific variable, such as rainfall, temperature, pressure, or elevation, and they are used to visualize the spatial distribution and patterns of that variable.