33. Which of the following is absent from the wall of small-diameter (~ 1 mm) bronchioles?
(A) Epithelium
(B) Cartilage
(C) Smooth muscle
(D) Blood vessels
(E) Elastic fiber
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統計: A(3), B(41), C(6), D(3), E(4) #3082792
統計: A(3), B(41), C(6), D(3), E(4) #3082792