Complex sentence: All four health regions offer primary care and secondary care services; however, only the Central Health Region, which serves the largest population in Belize, offers tertiary care services (see Health care delivery for description of levels of care).
Split into simpler sentences: All four health regions offer primary care and secondary care services. Only the Central Health Region, which serves the largest population in Belize, offers tertiary care services (see Health care delivery for description of levels of care).