Railroads made transportation easier and clipper ships are merchant ships which allowed trade between countries in a smooth manner.
Explanation:
Invention of huge railroads made america to tread inn the path of economic development. It changed the way humans travel and work. It enabled easier transportation of raw materials and finished goods. It allowed the rise of many towns and cities along the trail of railroads.
Clipper ships are the new invention wherein it clips to the water and it moves in a great pace. These are sailing vessels. the first clippers emerged inn American and British yards. Baltimore clippers were famous during war and it was used to carry huge supply of arms and ammunition during the war time.