What natural barriers offered Korea some protection from neighboring countries?

A mountainous barrier lies between Korea and its northern neighbor, Manchuria. Because of the mountains and the seas, Korea developed somewhat in isolation from its neighbors.

slavery, abortion, donald trump, gay marriage, racial rights, immigration  

explanation:

anything that has been broth up to the supreme court is something of grate political divide   so just look as court cases

1. it was caused by feudalism

2. charlemagne used christianity as a major cornerstone for his rule. cloisters were built all over the empire to act as centers for the (re)population of the vast european wilderness.

3. the europeans feared the next raid every time chetak

i'm not so sure about #6. but i hope i you with the first 3.