Which of the following did Mexico and the Republic of Texas continue to fig the location of the US Mexico border
the practice of slavery in Texas
the location of the Mexico-Texas border
the practice of slavery in Mexico

The answer is "The first choice".

Explanation:

In the 1840's the United States - Mexico boundary became "the easiest" theme "struggles" among "Mexico and Texas."

The "Republic of Texas" believed their "southern borders" were also the "Río Grande." They have even known them like "Mexicans" far south the Rio Grande.

Mexico failed to acknowledge the "Texas Republics" & "irregular disputes" between both the 2 countries that had "persisted" and during the 1840s.

The admission of Texas as "28th US territory" contributed directly to the "Mexican war" from 1845.

c. the dred scott v. sandford case,

the term is einsatzgruppen