Final answer:
The main reason that led to the Civil War was slavery. Oil rights and religious freedom were not direct causes of the Civil War.
Step-by-step explanation:
The main reason that led to the Civil War was slavery. The issue of slavery had been a point of contention between the Northern and Southern states for decades. The Southern states relied heavily on enslaved labor for their agrarian economy, while the Northern states had mostly abolished slavery.
While oil rights and religious freedom had their own significance in American history, they were not direct causes of the Civil War. Oil rights became more relevant during the 20th century with the rise of the petroleum industry, and religious freedom was a broader issue related to the growth of different religious groups in America.
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