Explain the Lewis and Clark expedition had four main objectives: 1.  Military reconnaissance; what would be good sites for forts and outposts for national defense against foreign and internal forces?  2. A topographical survey; (with a view to westward expansion) -- where were the mountains, rivers, natural resources, etc.  3. Establishing friendly and trade relations with Native American groups for, e.g., engaging in fur trade, but also because Jefferson desired to "civilize" and incorporate Native Americans into the Union.  4. An Enlightenment mission to observe, catalog, and categorize flora, fauna and animals.