Which event took place in 1950 and had the greatest impact on the course of the korean war?

North Korea invasion of the South.

Explanation:

In 1950 North Korea invaded South Korea which began the war.

After the war, Korea had been divided by the US and the Soviet Union into two parts, the communist(North) and capitalist(South). Both sides did not recognize the other and considered themselves as the only Korea, which led to the war.

hunsgi that's the correct answer

observing traffic laws in exchange for driving on the highway.