Which of the following is NOT an example of the Columbian Exchange? a
Native Americans began to hunt using horses.
b
Cartographers in Europe learned to draw more accurate maps.
c
Europeans were introduced to corn and beans.
d
Many Aztecs and Incas died of smallpox and other diseases.

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?