What role did the Kansas-Nebraska Act play in sectional tensions?

The Kansas-Nebraska Act played a significant role in exacerbating sectional tensions primarily by allowing the question of slavery to be determined by popular sovereignty in the new territories of Kansas and Nebraska. This meant that the settlers in these territories could decide for themselves whether to permit slavery, which activated intense competition between pro-slavery advocates from the South and anti-slavery supporters from the North.

The act effectively repealed the Missouri Compromise of 1820, which had previously established a geographical line prohibiting slavery in certain territories. By undermining this established framework, the Kansas-Nebraska Act led to violent conflicts, most notably "Bleeding Kansas," where pro- and anti-slavery forces clashed violently over control of the territory. This pivotal moment deepened the divide between the North and South and fueled the political landscape leading to the Civil War.

In contrast, the other options suggest outcomes that the Kansas-Nebraska Act did not achieve. The act did not resolve disputes over slavery (as implied by the first option), nor did it eliminate the need for slave codes, which were still enforced to regulate the behavior and rights of enslaved people. Lastly, rather than promoting peace, the act fueled animosities and hostilities between differing factions over the issue