Cathy and Sherri Must Finish All of Their Vegetables Before

Multiple Choice

Cathy and Sherri must finish all of their vegetables before they can have dessert.Cathy complains that Sherri doesn't have as much to finish as she does,even though both girls actually have the same amount on their plate (Cathy's vegetables were just more spread out) .Cathy's error stems from a failure to understand the concept of ____.

A) conservation
B) complementarity
C) concrete operations
D) object permanence