Lungs are held tightly to the wall of the thorax due to
A) the diaphragm and intercostal muscle contractions.
B) tight junctions between the lungs and the thorax.
C) surface tension of the pleural fluid and negative pressure in the cavity.
D) atmospheric pressure pushing on the lungs.
E) pulmonary ligaments that anchor the lungs.
Question 2
The primary cause of blindness in the United States is
A) cataracts.
B) diabetic retinopathy.
C) glaucoma.
D) retinal detachment.
E) retinopathy of prematurity.