Black children could not attend the same schools as white children. This is an example of?

Segregation. Segregation is the practice of separating people into different groups, usually based on race, gender, or other factors. In the United States, segregation was a major issue in the 20th century, as it was used to keep black people separate from white people in schools, public transportation, and other public facilities. Segregation was deemed unconstitutional by the Supreme Court in the famous Brown v. Board of Education case in 1954.