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 statement highlights the significant influence of slavery on the political and economic motivations behind Texas's secession. The election of Abraham Lincoln, who was seen as opposed to the expansion of slavery, raised concerns among slaveholding states about the future of their economic interests, which were heavily reliant on the institution of slavery.