In U. S. History, 19th Century use of the term "American Frontier" refers to A)
the area where pioneer settlement ended.
 
B)
the Atlantic or Pacific coast of North America.
 
C)
the territory east of the Appalachian Mountains.
 
D)
any territory beyond the thirteen original colonies.
 

A

Explanation:frontiers are borders and borders are where settlers arnt

the two things that develop a strong social foundation are: a. separation of church and states e. education received attention separation of church and states separate the illogical  argument that came from religious beliefs to a fact based belief. while education will make us remember the past to avoid the repeat of our mistakes.