A. The land dispute in Texas between Mexico and the United States in 1846 was about determining where did the borders of Texas lie, on Nueces River or Rio Grande.
B. U.S claim in the land dispute is supported by the map.
Step-by-step explanation:
In 1846, Mexico and U.S. started a war over Texas border. The conflict was over the border of Texas and where it ended, on the Nueces River which was Mexico claim or on Rio Grande which was U.S. claim.
In the end, U.S. won the war with the help of U.S forces who were victorious repeatedly against Mexicans. Even though U.S. entered the war, it was still divided as many people of influence did not support the act of war. But, anyhow, the result of the war was in favor of U.S. as seized more than 500,000 square miles in the end.