Final answer:
Executive Order 9981, issued by President Truman in 1948, marked the end of segregation in the military and promoted equal opportunity regardless of race, ethnicity, religion, or national origin.
Step-by-step explanation:
Executive Order 9981, issued by President Truman in July 1948, laid the mark of ending segregation in the military and promoting equal opportunity for all members regardless of their race, ethnicity, religion, or national origin. This executive order aimed to integrate the armed forces and ensure fair treatment and equal opportunity for all personnel. Although Truman's order did not specifically mention integration, it was intended to bring about racial integration within the military.