ii DECLARATION I hereby declare that this thesis report was conducted by me and it is a record of my own research work. It has not been presented before in any previous application for a higher degree. References made to published literature have been duly acknowledged. ………………………………. Date………………………… Yahaya Abbas Yakubu The above declaration is confirmed. ……………………………….. Date………………………… Dr. K.I Musa Chairman Supervisory committee