I don’t see any options to select from.
Answer:
1- The addition of Texas added to the happening to the Mexican-American War
2- The contention began, to a limited extent, over a contradiction about which waterway was Mexico's actual northern fringe: the Nueces or the Rio Grande
Explanation:
The fundamental driver of the war was the affirmation of Texas into the United States of America. Since Mexico didn't perceive Texas' freedom after their effective resistance to the Mexican government it was viewed as an intrusion into Mexican domain once Texas acknowledged the greeting into the United States.
