Who was the man who found the headwaters of the Mississippi River and later explored parts of the Rocky mountains and southern United States?

Which of the following lists correctly orders the earth's layers from its innermost layer to its outermost layer? a. mantle, inner core, outer core, crust b. crust, inner core, outer core, mantle c. crust, mantle, outer core, inner core d. inner core, outer core, mantle, crust