I need help on this one,I can't think of anything,please please help me!

In a brief paragraph for each,explain the following items contributed to a greater sense of independence and nationhood:

A. Louisiana Purchase

B. Embargo

C.War of 1812

D. John Marshall Supreme Court decisions
1. McCullough V. Maryland
2. Dartmouth College V. Woodward
3.Gibbons V. Ogden ( 1 paragraph is enough for all three)

E. Adams-Onis Treaty

F. Monroe Doctrine

Please Help Me!!!