Complex sentence: The abdominal cavity is one body cavity of the human body (and animal bodies) that holds the bulk of the viscera and which is located below (or inferior to) the thoracic cavity, and above the pelvic cavity.
Split into simpler sentences: The abdominal cavity is the body cavity of the human body (and animal bodies) that holds the bulk of the viscera. It is located below (or inferior to) the thoracic cavity, and above the pelvic cavity.