Achondroplasia is one of the most common types of dwarfism. Learn about its causes, diagnosis, and treatment. Achondroplasia is one of the most common types of dwarfism.
Westward Expansion (1807-1912) The Surge West. Summary. The westward movement of the American population occurred in intermittent flurries of settlement. The first began early in the nation's history, resulting in the statehood of Vermont, Kentucky, Tennessee, and Ohio, all of which were admitted to the Union between 1791 and 1803.
Westward Expansion. The second major impact Jacksonian Democracy had was westward territorial expansion. Under President James K. Polk, the U.S. annexed Texas in 1845, signed a treaty with Britain to split the Oregon territory in 1846 and fought a war with Mexico the same year to claim California and the Southwest.