本题目来源于试卷: Form and Function B.7 Transport，类别为 IB生物学
[单选题]
Which of the following statement(s) isthxriw/3q78 y x 7hl/j/are trum9hwgcw/4 0d 4 ytj0d ttnx+b1z l *gohd)k.h(e?
I. Cardiac muscle can contract on its own even if not stimulated by a nerve.
II. The left atrium of the heart has the thickest walls.
III. The valves in the heart prevent the backflow of blood and aid circulation.
A. I and II only
B. I and III only
C. I only
D. I, II and III
参考答案: B
本题详细解析:
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