Final answer:
The diaphragm divides the ventral body cavity into the thoracic cavity superiorly and the abdominopelvic cavity inferiorly, containing organs like the heart, lungs, and digestive and reproductive systems.
Step-by-step explanation:
The diaphragm, a flat muscular sheet, divides the ventral body cavity into a superior/cranial thoracic cavity and an inferior/caudal abdominopelvic cavity. The thoracic cavity sits above the diaphragm and is enclosed by the rib cage, containing vital organs such as the lungs and heart. The abdominopelvic cavity lies below the diaphragm and houses the digestive and reproductive organs. This separation is crucial for the function and protection of these organ systems.