Manifest Destiny is a doctrine that believes that United States has the right to expand accross the continent toward the west, toward the Pacific Ocean, as a design of Providence. Expansionism is a set of policies and actions of territorial acquisition and aggrandizement. These ideas or conceptions drove many of the USA actions and policies in the 19th century, and they were pursued with consistence by different administrations throughout the century. The USA finally reached its goal of extending its territory to the Pacifc shores after defeating Mexico in 1848 and forcing it to cede a huge territory that included California, Nevada, Arizona, New Mexico and parts of Colorado.
Crop rotation is when a farmer changes the crops grown in the same field each year to ensure he gets the best harvest possible by not exhausting the soil of specific nutrients by repeatedly growing the same thing.
