The correct answer to this open question is the following,
In my opinion, the development of the "American" economic system was an important change in the way the United States economy developed.
There were three specific "parts" of the "Market Revolution" in early 19th century America. Of these three, the most important were the technological innovations invented in order to develop mass production. Yes, the Industrial Revolution was characterized by a series of inventions that developed new machines that allowed mass production in the factories. And for me, that was the most important element of the three.
In the mid-1800s, the market revolution had changed the way Americans produced goods. New factories introduced new machinery to simplify the production process, producing more goods in less time, at much more affordable costs. This, with the improvement of the transportation systems such as the railroad and years later, teh Transcontinental Railroad that connected the East and the West coast of the United States, helped to change the face of trade in America.