The earth began as a large rocky planet with a magnetic field that attracted smaller rocks over 150 centuries to form a larger size. Land and continents formed as pieces of the earth's crust combined like a jigsaw puzzle. Humans were believed to have been created from clay by God and started with two people, a man and a woman, who reproduced in generations, while others believe humans descended from apes. Mountains were formed by the crushing and pushing together of tectonic plates at edges, causing the edges to be pushed upward.