Final answer:
The Civil War was primarily caused by the issue of slavery, as the Northern and Southern states had differing views on its abolishment and expansion.
Step-by-step explanation:
The Civil War in the United States was primarily caused by the issue of slavery. The Northern states, with their industrial economy, believed that slavery should be abolished, while the Southern states, with their agrarian economy, depended on slavery for their labor force. Other factors such as economic differences, states' rights, and political tensions also contributed to the outbreak of the war. However, the main catalyst was the dispute over slavery and its expansion into new territories.
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