Question

checkpoint 17
listen
what event led to the start of the korean war?
the soviet union invaded south korea.
the south korean army crossed the yalu river.
the north korean army crossed the 38th parallel.
the united nations forces landed at the bay of inchon.

Explanation:

The Korean War began when North Korea, supported by the Soviet Union and China, invaded South Korea. The 38th parallel was the boundary between North and South Korea. When the North Korean army crossed this boundary, it led to the start of the war. The Soviet Union did not directly invade South Korea. The South Korean army did not cross the Yalu River (which is the border between China and North Korea). The United Nations forces landing at the Bay of Inchon was a later event in the war, not the start of it.

Answer:

The North Korean army crossed the 38th parallel.