Question

president johnson began his presidency under difficult circumstances because he
had little public support and was elected by a narrow margin.
took office after his predecessor was assassinated.
was a teacher with little prior political experience.
took office after a disaster in the space program.

Explanation:

Lyndon B. Johnson became President of the United States in 1963 immediately following the assassination of his predecessor, John F. Kennedy, which created a sudden, traumatic, and politically challenging transition. The other options are incorrect: Johnson had significant political experience, he was not elected by a narrow margin initially (he took office via succession), and his presidency did not begin due to a space program disaster.

Answer:

took office after his predecessor was assassinated.