<prompt> Pedzisa mutsara unotevera: Vanotarisirwa navaAmerica vanoshandira makambani akazvimirira muVietnam havana kufukidzwa nomurayiro waPurezidhendi, uye naizvozvo dzidzo yaavo vanosarudza kuramba vari muSaigon gare gare yakapiwa nezvikoro zvakawanda zvakazvimirira zvakavambwa muSaigon pashure pokubviswa. Chimwe chezvikoro izvi chakadanwa kuti Phoenix Study Group, vane vadzidzi vakarondedzerwa se vana vavafundisi, vemabhizimisi vakapfuma uye vagari vemo veAmerica. Chikoro ichi chakapfuurira kuvapo kusvikira  <response>: kuwa kweSouth Vietnam kumasimba eNorth Vietnam muna April 1975. 