AGREEMENT AND PLAN OF MERGER BETWEEN AND AMONG NU SKIN ENTERPRISES, INC., NSC SUB, INC., NSG SUB, INC., NSM SUB, INC., NFB SUB, INC., NU SKIN CANADA, INC., NU SKIN GUATEMALA, INC., NU SKIN GUATEMALA, S.A., NU SKIN MEXICO, INC., NU SKIN MEXICO, S.A. de...