[Solved] Viruses that consist of only a nucleocapsid are considered A)simple viruses. B)complex viruses. C)naked viruses. D)viroids. E)incomplete viruses. Pharynx: The muscular tube at the back of the nose and mouth that connects them to the esophagus. Serous Fluid: A clear, watery fluid that lubricates the surfaces of membranes lining body cavities and organs. Pleura: Thin layers of tissue that line the lungs and the inside of the chest cavity, providing lubrication necessary for the lungs to move smoothly during breathing. Thorax: The chest cavity.