What was the line that held against the North Korean invasion called

38th parallel. 38th parallel, popular name given to latitude 38° N that in East Asia roughly demarcates North Korea and South Korea. The line was chosen by U.S. military planners at the Potsdam Conference (July 1945) near the end of World War II as an army boundary, north of which the U.S.S.R.

c.) biotic: snails; abiotic: temperature climate