Because they faced same challenges. The first one~ complex changes in the military technology and in the world economy, the second~ increasing difficulty of basing an extensive land empire on military forces paid through land grants.
Answer: Colonization put many ecosystems off course. Many colonies were bringing in organisms while many colonies were destroying them. The Europeans brought many diseases with them that put Native American populations at risk.
Explanation:
Main crops would be bananas and beans
The Frontier ended when all of the US was successfully settled one way or another
so True(?) if that is what it means,
hope this helps
U.S. foreign policy shifted away from "isolationish" to international involvement, mostly during and after World War II, when the United States emerged as the most powerful country on earth.
