Final answer:
Option a) pleural cavity lies between the lung and the chest wall, providing a lubricated surface for the lungs to expand and contract.
Step-by-step explanation:
The structure that lies between the lung and the chest wall is called the a)pleural cavity.
This cavity is part of the thoracic cavity and is the space between two layers of the pleura, which are the visceral pleura directly covering the lungs, and the parietal pleura, which is connected to the thoracic wall, the mediastinum, and the diaphragm. The pleural cavity acts as a lubricated sliding surface allowing the lungs to expand and contract with minimal friction during respiration.