Which three statements regarding the abdominal cavity are true?

The abdominal cavity is an essential part of human anatomy, and each of the statements presented highlights key characteristics and structures within it, confirming the correctness of the choice that includes all three statements.

The abdominal cavity is indeed bordered superiorly by the diaphragm, which serves as a muscular partition between the thoracic cavity and the abdominal cavity. This anatomical separation is crucial for various respiratory functions and provides structural support.

The mesentery, as stated, is a fold of peritoneum, which is a membrane that lines the abdominal cavity and covers the abdominal organs. This structure is vital for anchoring the intestines to the posterior abdominal wall while providing a conduit for blood vessels, nerves, and lymphatics to reach the intestines.

Additionally, the parietal peritoneum is the layer of peritoneum that is in direct contact with the abdominal wall, forming the outer layer of the peritoneal cavity. This anatomical aspect ensures that the organs within the abdominal cavity are supported and protected while allowing movement necessary for digestion and other bodily functions.

Since all three statements accurately describe components and characteristics of the abdominal cavity, the choice encompassing them all is the most appropriate response.