How and when were the Appalachians formed

The ocean con tinued to shrink until, about 270 million years ago, the continents that were ances tral to North America and Africa collided. Huge masses of rocks were pushed west- ward along the margin of North America and piled up to form the mountains that we now know as the Appalachians.

Explanation:

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.