Bodies of water, specifically rivers.
Answer:
An alliance is a union or association formed for mutual benefit, usually between countries or other organizations. This is seen as one of the causes of WW1 because countries involved in the developing conflict brought their allies into it as well. Serbia relied on their allies such as Russia, France, and Britain, while Austria called on the Ottoman Empire and Germany.
The correct answer would be C-intervention.
It is very much hard to answer.
It was mainly because of how the North and the South of America had different lifestyles and economy's. You would be surprised to know that the Democratic party back then supported Slavery and the republicans dint support Slavery.
Plain Answer: Because of Slavery, Way of Life and Different Economy. The Democratic Party would do anything to keep themselves supported.