What type of attraction exists between the two pleural layers?

The attraction between the two pleural layers is primarily cohesive due to the presence of pleural fluid that allows them to stick together. This cohesive force is crucial for the functioning of the respiratory system, as it helps maintain the negative pressure within the pleural cavity. This negative pressure is essential for lung inflation during breathing because it creates a gradient that facilitates the expansion of the lungs as the diaphragm and intercostal muscles contract.

Cohesion in biological systems often relates to the attraction between similar molecules, which is precisely what occurs with the pleural fluid and the mesothelial cells on the surfaces of the pleurae. This cohesive attraction prevents the lungs from collapsing and keeps them closely adhered to the chest wall during inhalation and exhalation.

The other options do not accurately describe the interactions between the pleural layers. Magnetic interactions do not occur in this context, and repulsive forces would not help in maintaining the necessary pressure for effective breathing. Therefore, cohesive attraction is the key mechanism that sustains the pleural layers' relationship and supports respiratory function.