USA HISTORY

Detailed explanation-1: -The annexation of Texas contributed to the coming of the Mexican-American War (1846-1848). The conflict started, in part, over a disagreement about which river was Mexico’s true northern border: the Nueces or the Rio Grande.

Detailed explanation-2: -Texas formally joined the union on February 19, 1846. Following the annexation, relations between the United States and Mexico deteriorated because of an unresolved dispute over the border between Texas and Mexico, and the Mexican–American War broke out only a few months later.

Detailed explanation-3: -By its terms, Mexico ceded 55 percent of its territory, including the present-day states California, Nevada, Utah, New Mexico, most of Arizona and Colorado, and parts of Oklahoma, Kansas, and Wyoming.

Detailed explanation-4: -In 1821, the Mexican War for Independence severed the control that Spain had exercised on its North American territories, and the new country of Mexico was formed from much of the lands that had comprised New Spain, including Spanish Texas.