Question

what is true about the border states during the civil war? they all eventually join the north. they all eventually join the south. they all had slaves but never secede. they are the only free states to join the confederacy.

Explanation:

The Border States (Delaware, Kentucky, Maryland, Missouri, and West Virginia later) were slave states that remained part of the Union during the U.S. Civil War, never seceding to join the Confederacy. The other options are incorrect: they did not all join the South, they were not free states joining the Confederacy, and while they stayed in the Union, the phrasing "join the North" is inaccurate as they remained in the existing Union rather than joining a separate Northern faction.

Answer:

They all had slaves but never secede.