Development of more railroad systems contributed
most to US westward expansion in the second half of the nineteenth century.
The correct answer between all the choices given is the second choice or
letter B. I am hoping that this answer has satisfied your query and it will be
able to help you in your endeavor, and if you would like, feel free to ask
another question.
The Northern European plain and lowlands of West Siberian Plains have a lot of differences in terms of their characteristics. The only similarity between the two would be the vast complex land that both of these lands have.
I hope this answered your question.