Complex sentence: The Seattle Colleges District is comprised of public, state-supported institutions, individually accredited by the Northwest Commission on Colleges and Universities, an institutional accrediting body recognized by the Council for Higher Education Accreditation and the United States Department of Education.
Split into simpler sentences: The Seattle Colleges District comprises public state-supported institutions, individually accredited by the Northwest Commission on Colleges and Universities. This is an institutional accrediting body recognized by the Council for Higher Education Accreditation and the United States Department of Education.