Why did the Kansas-Nebraska Act of 1854 increase the intensity of the national debate over the expansion of slavery?

Choose what you like of the following questions?
1. Lincoln said, “A house divided against itself cannot stand.” Why did the spread of slavery become such a divisive political issue in the 1840s?
2. How did Abraham Lincoln and Stephen Douglas convey their ideas of freedom during their famous debates? How did their views differ on the expansion of slavery, equal rights, and the role of the national government?
3. Why did the Kansas-Nebraska Act of 1854 increase the intensity of the national debate over the expansion of slavery? What was so controversial about it? How did it intersect with the Missouri Compromise of 1820? What was “Bleeding Kansas”?
4. Analyze the significance of the 1857 Dred Scott decision in the developing sectional split. Why was the Supreme Court ruling in this court case notorious?
5. What was the Fugitive Slave Act of 1850? Why was it a major setback for abolitionists?
6. Why was the Mexican War viewed as a crisis of American democracy? How did it compel Henry David Thoreau to write “Civil Disobedience”?
7. What was California like after Mexico ceded it to the United States? Why did it achieve rapid population growth and ethnic diversity? Was it a free or slave state?
8. Discuss the early history of Texas. How did it become independent? What is legendary about the Alamo? How did Texas become part of the United States? How was Sam Houston, Governor of the State of Texas, reacting to the southern secession movement?
9. John Brown was a militant abolitionist. How did he wage a war against slavery? How did he become a martyr? How did he spark the Civil War?
10. Why did the American South start the secession movement? How was the Confederacy (Confederate States of America) different from the Union?