Why was separation of the races required in 1955?

Racial segregation.

Explanation:

Racial segregation took place in the United States from the late 19th century to the late 1950s. It is a kind of separation of people by race. Areas and public areas where black people could move were intended. It was a discriminatory and uncivilized practice. There were facilities that the black population could not enter, and they could only sit in certain places on public transport. Racial segregation was a process that was abolished by the enactment of a series of laws in 1964. These laws abolished segregation and discrimination of the population.

i really dont know the answer

c it says nothing about connecting those 2 seas.