In chemical compounds, atoms like to have 8 electrons in their outer shell, this gives them
a. the electron configuration of a noble gas
b. more protons than electrons
c. eight electrons in their principal energy level
d. more electrons than protons

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: