Oxygen's atomic number is 8. This means that an oxygen atom has *
2 poin
8 neutrons in its nucleus
a total of 8 protons and neutrons
8 protons in its nucleus
a total of 8 neutrons and electrons

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).