Interdependence and Trade But, this gives rise to two questions Why is interdependence the norm? What determines production and trade? Harcourt, Inc. items and derived items copyright C 2001 by Harcourt, Inc.Harcourt, Inc. items and derived items copyright © 2001 by Harcourt, Inc. Interdependence and Trade But, this gives rise to two questions: Why is interdependence the norm? What determines production and trade?