1. James K. Polk was a strong advocate of ____________, which ultimately led to the Mexican-American War. 2. The annexation of Texas by the United States in ____________ sparked tensions and disputes between the two nations. 3. The border between Mexico and the United States was a subject of contention, with Mexico claiming the ____________ as the border and the United States arguing for the ____________. 4. Zachary Taylor, the commander of the U.S. Army forces in Texas, led American troops to the ____________, further escalating tensions. 5. Stephen Kearny led the Army of the West and captured ____________, the capital of New Mexico, without firing a shot. 6. The Republic of California was established by American settlers in the region during the Mexican-American War, forming the ____________. 7. Winfield Scott, the commanding general of the U.S. Army, led a successful campaign to capture ____________, the capital of Mexico. 8. The Treaty of Guadalupe Hidalgo, signed in ____________, ended the Mexican-American War and resulted in the annexation of Texas and the cession of a vast territory to the United States. 9. The Gadsden Purchase, made in ____________, involved the acquisition of a strip of land in present-day Arizona and New Mexico. 10. The discovery of gold in California in ____________ led to a massive influx of people known as the "Forty-Niners." 11. James K. Polk was the ____________ President of the United States. 12. Texas declared independence from Mexico in ____________ and had been an independent republic for nearly a decade. 13. Mexico claimed that the border between Mexico and the United States was the ____________ River. 14. Zachary Taylor was appointed as the commander of the U.S. Army forces in ____________. 15. The Treaty of Guadalupe Hidalgo resulted in the cession of territories including ____________, New Mexico, and parts of Colorado and Wyoming.