The statement that best explains how slavery affected Texas’s decision to secede from the Union is:
The election of Lincoln in 1860 threatened the economic power of plantation owners in Texas.
This response highlights the direct link between the fears of plantation owners losing their economic power, which was heavily dependent on slavery, and the political developments leading to secession. Lincoln's election was seen as a threat to the institution of slavery, prompting Texas and other Southern states to seek secession to protect their economic interests.