Final answer:
The Selma to Montgomery marches most helped pass the Civil Rights Act of 1964.
Step-by-step explanation:
The event that most helped to pass the Civil Rights Act of 1964 was the Selma to Montgomery marches. These marches were part of the voting rights movement in Selma, Alabama, and they highlighted racial injustice and the desire of African American citizens to exercise their constitutional right to vote. The marches contributed to the passage of the Voting Rights Act that same year, which was a landmark achievement of the Civil Rights Movement.