Which of the following did Mexico and the Republic of Texas continue to fight about in the 1840s?
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 location of the US-Mexico border

Explanation:

the answer is the US-Mexico Border because that event was unsolvable back then,which was a big factor leading to the Mexican-American War.

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.  

the correct answer is b