I would argue that the primary difference was the introduction of nuclear weapons after WWII--meaning that the spread of communism could actually take over the world as opposed to just causing unrest in the US.
The answer would be C, different economics, because the northern states were going through an economic boom, due to industrialization. The southern states were running on slave labor.
Answer:
Different kinds or sorts.
Explanation:
For example, we have a diverse group of students in our class.
Answer: The treaty established the boundary of U.S. territory and claims through the Rocky Mountains and west to the Pacific Ocean, in exchange for the U.S. paying residents' claims against the Spanish government up to a total of $5,000,000 and relinquishing the U.S. claims on parts of Spanish Texas west of the Sabine River
Hope this helps :)