Answer:
The acquiring of the territories gave the United States justification to send out immigrants into those territories and settle the land along the trails created by traders and trappers beforehand. These immigrants and other workers then set up the Transcontinental Railroad to facilitate trade and transport back and forth from the west coast to the east.
A because they are always needed in every situation.
Divide
Answer needs to be 20 characters, so I am adding filler.
Answer:
Letter C which is Military
