Final answer:
The Kansas-Nebraska Act of 1854 increased tensions over slavery and led to the formation of the Republican Party. The Act repealed prior compacts and introduced popular sovereignty to new territories, contributing to a more divided national political landscape and escalating conflicts.
Step-by-step explanation:
The correct cause and effect statement that MOST accurately describes the results from the Kansas-Nebraska Act of 1854 is: Cause: Increased tension over slavery; Effect: Formation of the Republican Party. The Act was introduced by Senator Stephen Douglas and it threw the country into further turmoil over the issue of slavery.
It repealed the Missouri Compromise and opened new territories to the possibility of slavery through the concept of popular sovereignty. This division and conflict led to the foundation of the Republican Party, which drew together northern Whigs, Democrats who opposed the Act, members of the Free-Soil Party, and abolitionists.
The passage of the Kansas-Nebraska Act had far-reaching political ramifications, including the eventual breakdown of the second party system as the Whigs declined and the Know-Nothings and Republicans emerged. As a result of the Act, conflict in Kansas grew increasingly violent, becoming known as 'Bleeding Kansas', and pushing the nation closer to the brink of Civil War.