It shall be the duty of the Planning Commission to study the Township from its commercial, industrial, social, economic and agricultural phases. From its study and continued concern with such matters, the commission periodically and continually reviews the basic plan of the Township known as the "Egelston Township general development guide," reviews this chapter and map of the community, recommends on a continuing basis to the Township Board any changes or revisions in the same that should be accomplished, and holds statutory hearings on requested changes in zoning and submits recommendations regarding same to the Township Board. In addition, the Planning Commission, by this chapter, and in accordance with state law, has sole responsibility for decisions regarding site plans, special land uses and planned unit developments which may be submitted for the development of land in accordance with this chapter.