Which event brought momentum to the movement to lower the voting age from 21 to 18?

persian gulf war

vietnam war

world war i

korean war

Atherapist at a free university clinic treats elementary school children with behavior problems who are referred by a social service agency. she is also a doctoral candidate who proposes using data she has and will collect about the children for a case-based research project. describe the type of parental permission which is required in this case?