5. __________ in the circulatory system typically operate under lower internal pressure, carry blood toward the heart, contain valves that prevent backflow, and have relatively thin walls with relatively less smooth muscle and elastic tissue.
(A) Arteries
(B) Veins
(C) Capillaries
(D) Lymphatic vessels
(E) Arterioles
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統計: A(0), B(4), C(0), D(0), E(0) #3853310
統計: A(0), B(4), C(0), D(0), E(0) #3853310