Final answer:
The outbreak of the Civil War was triggered by the issue of slavery and led to secession. Major Robert Anderson barricaded himself in Fort Sumter.
Step-by-step explanation:
The outbreak of the Civil War was triggered by the issue of slavery. The disagreement between the Northern and Southern states regarding the institution of slavery led to tension and ultimately secession. Besides South Carolina, two other states that seceded from the Union were Mississippi and Florida.
The soldier who barricaded himself in Fort Sumter was Major Robert Anderson.
Learn more about Causes of the Civil War