How did scientists calculate the most exact value for the mole? through the charge of an electron and Faraday’s constant
through counting the atoms in a sample of carbon-12 under a microscope
through x-ray diffraction of silicon atoms

the atomic mass is the bottom number on the element.

-steel jelly

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: