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.
Many Americans claimed that the United States had a manifest destiny to expand westward to the Pacific Ocean. U.S. attempts to purchase from Mexico the New Mexico and California territories failed. In 1846, after a clash of Mexican and U.S. troops along the Rio Grande, the United States declared war. American troops occupied the lightly populated territory of New Mexico, then supported a revolt of settlers in California.