Explanation:
The strategy of "containment" is best known as a Cold War foreign policy of the United States and its allies to prevent the spread of communism after the end of World War II.
“The political geography of this nation was a product of various treaties and acquisitions that eventually resulted in the country extending from the Atlantic to the Pacific Ocean.”
So the answer must be:
C.) The United States gained the area between the Atlantic Ocean and Appalachian Mountains from the original thirteen colonies in 1770.
Interacting groups shared skills and ideas that improved farming practices
