Answer: diaphragm
Explanation:
The diaphragm separates the thoracic cavity from the abdominal and pelvic cavity.
The diaphragm is a sheet of internal skeletal muscle located below the thoracic cavity that houses the heart and lungs. Below the diaphragm is the abdominal cavity.
The diaphragm plays an essential function for respiration. When the diaphragm contracts, the volume of the thoracic cavity increases so that air is drawn into the lungs.
