Final answer:
The term 'predecessor' means a person who held a job or office before the current holder; John F. Kennedy was Lyndon B. Johnson's predecessor. Johnson inherited the presidency and continued Kennedy's initiatives, especially in the areas of civil rights and healthcare.
Step-by-step explanation:
The word predecessor refers to a person who held a job or office before the current holder. In the context of Lyndon B. Johnson (LBJ) becoming president after the assassination of President Kennedy, Kennedy was Johnson's predecessor. After Kennedy's assassination, the presidency was quietly transferred to LBJ according to the Constitution, demonstrating the effectiveness of the American system of presidential succession. Johnson used Kennedy's legacy to push for significant legislation, such as the Civil Rights Act of 1964, as well as healthcare programs like Medicare and Medicaid, seeking to continue the work and vision of Kennedy's administration. The transition of power reflected the constitutional processes established for such events, subsequently reinforced by the 25th Amendment.