Final answer:
Utah began to change in the early 1800s after the Mexican-American War when the Treaty of Guadalupe Hidalgo ceded Utah to the United States. Congress incorporated Utah into a territory in 1860 and Brigham Young was appointed as the territorial governor.
Step-by-step explanation:
In the early 1800s, Utah began to change after the defeat of Mexico in the Mexican-American War. The signing of the Treaty of Guadalupe Hidalgo ceded much of the modern-day American Southwest, including Utah, to the United States. Utah was incorporated into a territory by Congress in 1860, and President Millard Fillmore appointed Brigham Young as the territorial governor.