I'm not 100% sure but it could be: Voluntary Exchange takes place between buyers and sellers:
(btw I copied and pasted from the question so I didn't take any content :D)
The Pacific Railroad<span> Act chartered the Central Pacific and the Union Pacific </span>Railroad<span>Companies, and tasked them with building a </span>transcontinental railroad<span> that would link the United States from east to west. ... This affected the Native Americans in a negative way because the Native Americans used buffalo for many things.</span>
New Hampshire would not be considered apart of the 13 colonies
Religion were tolerated
currancy was gold and etc
Great question! Although I need you to share an image of the graph so I can help you with your question, as soon as you do I shall gladly help you out.