10th pick -- Geography: The Foundations
At long last, the new world took shape. Continents, chasms, mountains, and all manner of beautiful geography adorned its surface. Pr'Jah, the Master of Earth, was pleased. But he knew that in time, the world would grow stale. The plentiful forms of life that inhabited the world would eventually discover all there was to know of it, and would be damned to eternal complacency if there were no changes. So, as his final gift to the world, he created The Foundations, the mechanism by which the world itself would evolve and change.
What do The Foundations involve, exactly? Plate tectonics? A giant world machine powered by tidal forces from the world's three suns? Turtles all the way down? The Foundations encompass all of these things and much more, in a great and complex system that will guarantee change and growth for all the world for millennia to come.
Note: The Foundations includes a vast, worldwide network of caverns that reach to all places on the surface of the planet--even the 'Gluteal Cleft of the World'.