Question

Which of the following factors best explains the territorial expansion of slavery in the middle of the nineteenth century?

Answer 1

Answer: The Mexican american war incorporated extensive new lands into the United States.

Answer 2

The expansion of US territories

Step-by-step explanation:

Jefferson's acquisition of the Louisiana territories in 1803 doubled the size of the US coupled with the victory in the Mexican-American War extending the U.S territories to the Pacific which further tripled its area. This expansion invariably led to the spread of slavery.