why greeks believed naturalism and realism in sculpture expressed something important about their cultural

Because different from Assyrians and Egyptians from whom the Greeks took inspiration, the greek sculpture represents the essence of a people who used to be rational. What does it mean? It means that the Greek people saw the world exactly as it was, and they tried to emulate. In the case of the sculptures, they wanted to capture the beauty, youth, and the essence of humanity. Despite idealized in some points, the Greek sculpture was an attempt to immortalize the human essence.

Explanation:

Egyptian sculptures were static, showed no movement, and portrayed, especially, Pharaoh. The Greeks, in turn, managed to give these static representations movement, idealized or perfect beauty, as well as balanced proportions.  Gradually, the arms extended by the body gained some movement at the same time that the muscles protruded from his sculptures and other details were added, such as the hair.

keeping a cash reserve because cash flow is the the movement of money through a company and if it just sits there, it wont the movement