Nobody knows what exactly causes canker sores, but many things may contribute to their development, such as certain medications, trauma to the mouth, poor nutrition, stress, bacteria or viruses, lack of sleep, sudden weight loss, and certain foods such as potatoes, citrus fruits, coffee, chocolate, cheese, and nuts.
civil rights movement definition. The national effort made by black people and their supporters in the 1950s and 1960s to eliminate segregation and gain equal rights.
social movement. 1. a group of diffusely organized people or organizations striving toward a common goal relating to human society or social change, or the organized activities of such a group: The push for civil rights was a social movement that peaked in the 1950s and 1960s.