Boa constrictors and pythons lack external limbs but their skeletons reveal bones of tiny hindlimbs. What structure is represented in this example

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?