A perforated state is a state that .
is completely surrounded by another state
serves as a buffer between two much larger states
stretches a long way in one direction, but a comparably short way in the other direction
is small and highly centralized
completely surrounds another state
If the political barrier between two states is the 50th parallel on the lines of latitude, then the boundary between those two states is known as a(n) .
physical boundary
arithmetic frontier
intermediate boundary
geometric boundary
buffer state