For one thing, the fact that replacing a natural; human leg with an artificial and accurate replacement is a stunning work of a cooperation of science and technology. The science comes in where the leg is applied to what still exists of natural flesh and bone, and how to make that adhere to the foreign object; a prosthesis. And on the other hand, it is a technological wonder on the grounds that the various mechanics that would allow this replacement leg to work and function with the human host requires the invention and intelligence to conceive and make a reality.