Which event directly leg to the end of the vietnam war

Direct U.S. military involvement ended on 15 August 1973 as a result of the Case–Church Amendment passed by the U.S. Congress. The capture of Saigon by the NVA in April 1975 marked the end of the war, and North and South Vietnam were reunified the following year.

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.

hello there, can you add the "following" multiple choices