45. In order for blood to always flow unidirectionally through a closed circulatory system, the_______.
(A) blood vessels farthest from the heart must have valves
(B) capillaries must have a thick endothelium
(C) arteries must be elastic
(D) pressure in all vessels must be equal

答案:登入後查看
統計: A(1), B(0), C(0), D(2), E(0) #3056708

詳解 (共 1 筆)

#7111146
1. 題目解析 這道題目的核心在於理解...
(共 847 字,隱藏中)
前往觀看
0
0