Final answer:
The American Civil War was mainly caused by divisions over slavery, economic differences, and political tensions, catalyzed by Abraham Lincoln's election in 1860. It ended with significant social, political, and economic changes, including the abolition of slavery and the rise of federal power.
Step-by-step explanation:
The causes of the American Civil War were complex and multifaceted, including economic, social, and political factors. Central among these was the issue of slavery, which deeply divided the nation. In the North, there was a growing movement against slavery's expansion, while in the South, the economic reliance on slave labor was deeply entrenched. The 1860 election of Abraham Lincoln, who was perceived as anti-slavery, triggered secession by eleven Southern states, eventually forming the Confederate States of America. While historians debate the proportions in which these factors contributed to the outbreak of war, the preservation of the Union and the abolition of slavery emerged as the defining outcomes of the conflict.
The Civil War had profound and lasting impacts on American society. It marked a significant shift in the balance of power, with the federal government asserting dominance over states. It also ended the plantation economy in the South while boosting the industrial economy in the North, leading to significant social and economic changes. The war led to the Emancipation Proclamation, which paved the way for the eventual abolition of slavery and transformed the lives of millions of African Americans.