A map showing the continental United States. Areas designated on the map include the original 13 colonies, the Florida Territory, the Louisiana Purchase, the Texas Annexation, Mexico, the Mexican Cession, The Oregon Territory, the Gadsden Purchase, and the British Cession of 1818. Review the map above. How did the idea of Manifest Destiny affect the U. S. border throughout the 1800s

americans pushed westward taking lands past the Appalachians and towards the west coast

the answer to your question is a. the salt plains

in 1811, he led an expedition, known as the george c. sibley expedition, to improve relations with the pawnee and kansa tribes, and also to locate the rumored jefferson's salt mountain

united states reinforcements contributed greatly to three allied victories in france at: cantigny (first major american battle), argonne (the largest in the united states military history, involving 1.2 million american soldiers), and château-thierry (one of the first actions under general pershing).