Final answer:
The record that contradicted white doubts regarding African American casualties during the war was the high number of casualties caused by racial discrimination.
Step-by-step explanation:
The record that contradicted white doubts regarding African American casualties during the war was the high number of casualties that were caused by racial discrimination. African American men and women faced severe discrimination and violence both on and off the battlefield, often at the hands of white people. Incidents such as the Zoot Suit Riots and racial incidents at military bases showed that the casualties were not a result of natural causes but were a consequence of racial tensions and discrimination.