When land is completely bare, with no topsoil present, the process of occurs on this newly formed land.
primary succession
secondary succession
tertiary succession

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate