What does the pleura serve to protect?

The pleura is a double-layered membrane that surrounds and protects the lungs. This membrane plays a crucial role in providing a frictionless surface for the lungs to expand and contract during breathing. The inner layer, known as the visceral pleura, is attached to the lung surface, while the outer layer, called the parietal pleura, lines the chest wall and diaphragm.

The pleura also helps prevent infection by providing a barrier to pathogens and plays an essential role in maintaining the negative pressure within the pleural cavity, which is necessary for proper lung inflation. Thus, the pleura is specifically designed to safeguard the lungs, making it the correct answer.

Other options, such as the heart, liver, and kidneys, are protected by different anatomical structures and membranes, which are not related to the pleura. For instance, the heart is encased in the pericardium, and the liver and kidneys are supported by their own protective layers or peritoneal cavities, demonstrating that each organ has its specific protective mechanisms.