The sentence that best completes the diagram is: Northerners and southerners grow more politically divided.
The Issue of Slavery in America
The issue of slavery became a political issue in the mid-1800s.
The conflict began with the addition of more territories gained from Mexico.
Northern states wanted to outlaw the practice of slavery in the West.
Southern states wanted to maintain the practice of slavery as their occupation was based on agriculture.
The issue of slavery divided both groups and formed the Confederate and the Union.
Thus option D is the correct answer.
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