Respuesta :
The simple answer would be: The Pony Express and/or Transcontinental Highway,
The Missouri river provided transportation in the early years of the United States.
The Missouri river which is the longest river in the United States, was a major transportation route for the western fur trade in the 18th century. Steamboats were used to move goods along the river.
The Missouri river was the major transportation route until the 19th century when the cross-continental rail roads was expanded.
Therefore, The Missouri river provided transportation in the early years of the United States.
Read more on Missouri river here
https://brainly.com/question/17535272