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.
South wanted slavery, rebellions because of Lincoln becoming president, John Brown's and other abolitionists actions, the consequences caused by Compromise of 1850, the consequences of the Fugitive Slave Act, and the controversy and Bleeding Kansas.
Rationalism led to the use of empiricism, or observation, in science. Francis Bacon invented the scientific method based on rationalism. It also lessened overbearing religious dogma
