Which cavity contains the heart and major blood vessels?

The correct response identifies the pericardial cavity as the space that specifically contains the heart and the major blood vessels connected to it. This cavity is a fluid-filled sac that surrounds the heart, providing it with lubrication and protection while also allowing for the heart's movements during the pumping cycle.

In contrast, while the thoracic cavity is a larger space that houses the heart, lungs, and other structures, it is not specific to just the heart and its major vessels. Similarly, the mediastinum is an anatomical region within the thoracic cavity that separates the lungs and contains the heart, trachea, esophagus, and other structures, but it does not exclusively refer to the area around the heart. Lastly, the pleural cavity is associated with the lungs, housing the pleural membranes surrounding each lung, rather than the heart. Therefore, the pericardial cavity is the most precise answer to indicate where the heart and its primary vessels are primarily located.