Question

multiple choice question
the parietal and visceral pleura are held closely together due to attractions between______.
o carbohydrates in the serous fluid and the moist membrane surfaces
o phospholipids making up the pleural membrane structure
o water molecules in the serous fluid and the moist membrane surfaces
o proteins on the surfaces of both pleural membranes

Explanation:

The parietal and visceral pleura are serous membranes. Serous fluid contains water molecules. The cohesion of water molecules (due to hydrogen bonding) and their adhesion to the moist membrane surfaces (due to polarity) hold the two pleurae closely together. Carbohydrates in serous fluid are not the main factor for this close - holding. Phospholipids in the membrane structure are part of the cell membrane composition but not directly responsible for the attraction between the two pleurae. Proteins on the membrane surfaces are involved in other functions like transport and signaling, not the main force for holding the two pleurae together.

Answer:

water molecules in the serous fluid and the moist membrane surfaces