Count the significant digits in each of these measurements: measurement number of significant digits −×2.010−3kJ/mol 72600.kg 0.007700J ×5.710−1mL

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:

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).