The correct answer is D) completion of the Transcontinental railroad in 1869.
<em>The event that would be best to use as supporting evidence in your speech would be the completion of the Transcontinental railroad in 1869.</em>
If you are giving a speech to your class about reasons why the United States rapidly formed over a dozen states in the West between 1850 and 1900, the event that would be best to use as supporting evidence in your speech would be the completion of the Transcontinental railroad in 1869.
On May 10, 1869, the Construction of the Transcontinental Railroad ended in Promontory, Utah. Finally, the East and the West were connected by train due to the work of many people in the companies Union Pacific and Central Pacific. The Pacific Railroad Act of 1862 allowed the construction and the West part of the territory could grow and prosper due to trade and better transportation of goods, supplies, and people.
