Biology 2005 JAMB Past Questions - Question 19: The mammalian lung is made airtight by the

Correct Answer

C

Explanation

— Each lung is directly surrounded by anouter and inner pleural membranes pleura. These pleura form a water proof andair tight sac. The space between the membranes is called pleural cavity and itencloses fluid. The fluid makes the lungs to move smoothly and slide over eachother. Diaphragm is muscular sheet which separates the thorax from theabdomen Mucousmembrane is the membrane that lines the inside of the respirator system (nasal passages, tracheabronchi etc) and alimentary canal which secrete mucus that keeps the surface moist.