Select the correct features of pleura from the following.
a. Double layered membrane with pleural fluid within.
b. Reduces friction on the lung surface.
c. The outer pleural membrane is in close contact with the lung surface.
Lungs are covered by a double layered pleura, with pleural fluid between them. It reduces friction on the lung-surface. The outer pleural membrane is in close contact with the thoracic lining whereas the inner pleural membrane is in contact with the lung surface.