What property of matter does not change even though the appearance may a) volume b) area c) shape d) mass

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

if you're asking what comes out, it's steam.