Final answer:
The most accurate statement about the Missouri Compromise (1820) is Option 3: It established a line dividing territories where slavery was allowed and prohibited.
Step-by-step explanation:
The most accurate statement about the Missouri Compromise (1820) is Option 3: It established a line dividing territories where slavery was allowed and prohibited.
The Missouri Compromise was a legislative agreement that aimed to maintain the balance between free and slave states in the United States. It allowed Missouri to enter the Union as a slave state and Maine as a free state. Additionally, it established the 36°30' line as the boundary to divide territories where slavery was allowed and prohibited.
This compromise was important because it temporarily eased tensions between the North and South regarding the expansion of slavery. However, it was ultimately overturned by the Kansas-Nebraska Act in 1854, leading to further conflicts and the eventual outbreak of the Civil War.