骨是一种器官，它的构造下列哪个答案正确()
A. 骨膜、骨密质和骨髓
B. 骨质、骨膜和骨髓
C. 黄骨髓、骨膜和骨松质
D. 红骨髓、骨密质和骨膜
将肋骨按其在体内的位置划分，下列哪个答案是正确的()
A. 附肢骨
B. 中轴骨
C. 扁骨
D. 短骨
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A. Tegmark fears he may hold the record for the longest time taken to read one book.
B. In a more positive vein， this is a wonderful collection of essays to dip in and out of if you already have a good overview （概述） of current cosmic understanding.
C. Levy is an active astronomer and an accomplished writer， so you"d expect him to provide a broad and accurate picture of our current understanding of the cosmos.
D. Scientific American has attempted to cater to this need by bringing together essays that have appeared in the magazine.
E. To some extent， these could have been plugged with a glossary （词表）. of terms.
F. Also included are contributions on the world of subatomic particles， the origin of life on the Earth and the possibility of its existence elsewhere.
全身骨显像摆位时，双脚趾尖并拢向前，双足跟分开的目的是()
A. 膝关节显像清晰
B. 踝关节显像清晰
C. 足小关节显示清晰
D. 胫骨与腓骨分开
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