Which of the following separates the lungs?

The mediastinum is the anatomical space located between the left and right lungs in the thoracic cavity. It encompasses various vital structures, including the heart, trachea, esophagus, and major blood vessels. By acting as a partition, the mediastinum effectively separates the lung tissues from each other, allowing them to function independently while also providing space for the other thoracic organs to operate without interference.

Other options do not fulfill the role of separating the lungs. The pericardial cavity is specifically the space surrounding the heart, while the abdominal cavity pertains to the abdominal organs and does not relate to the lungs. The pleural cavity, on the other hand, is the space between the pleura (the membrane surrounding each lung) and contains fluid that facilitates lung movement but does not serve as a divider for the lungs themselves.