Which substance is a greenhouse gas that is emitted by human activities, is the most widespread, and remains in the air the longest? vapor
methane
fluorinated gas
carbon dioxide

carbon dioxide emitted by human activities

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:

diaria maybe go see a doctor about that