Why did the republicans decide not to select burr as a candidate for vice president in the election of 1804

Alexander Hamilton, the first secretary of treasury of the United States, publicly endorsed Thomas Jefferson (Aaron Burr's competitor), leading to Jefferson's presidency. Wanting a democratic republican for a vice president, Jefferson reformed the party to get rid of Burr, with the argument that it didn't make sense to have the runner-up become the vice, seeing as the two individuals would have differing views on political, social, and economic issues. 

The correct answer is the hindu kush mountains.

Southern secession is the event or issue that historians can gain insight from this excerpt.