What event led the southern states to secede from the Union? (a)  

The Southern economy was more dependent on slave labor due to this industry (a)  

Someone who opposes slavery is known as a (a)   .

For many voters, the election of 1860 was about the future of ​ ​ ​ (a)  

Invented by Eli Whitney, this led to an increase of slave labor: (a)  

The Pacific Railroad Act allowed for this construction of this railroad to begin (a)  

This famous abolitionist was born into slavery, escaped, and then became influential by writing to newspapers all over the world. (a)  

A network of routes used by runaway slaves was called (a)  

The 13th, 14th, 15th Amendments of the U.S. Constitution are known as the "​ (a)   " Amendments.

Who was elected president in 1860, in turn causing some southern states to seced? (a)  

After the election of ​ (a)   , several southern states, beginning with South Carolina, seceded from the Union.