The peninsula between North Korea and South Korea was established by the Demilitarized Zone between 1950-1953 So the answer is D
I can’t really understand you if you speak in English I might be able to help you.
Oceans being joined together helps me understand the impact of a river being dried up because rivers lead to the ocean, once a river is dried up not only does that cut off a stream to the ocean it also affects animals. There’s many animals who live by water or live in water, and without it they wouldn’t be able to thrive. For example, some animals might stay near water to catch fish to eat and survive. Without the water, there are no fish.. but without the fish, that animal that was reliant on the fish wouldn’t be able to survive. A river drying up could also affect humans who live by water, and who use the stream as a water source. It could affect fisherman’s businesses and even food source if there’s no water. Oceans being conjoined together also help me understand the impact because if the Pacific Ocean just randomly dried up, it would affect the rest. The same as a river, if too many dry up it could eventually effect the ocean itself.
As I said in your other post/question on the same topic, you have to rephrase your question in order for us to help you. =)