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T的enzyme是在細胞分裂fast的時候產生，所以兒童體內的這種T比較多，成年人則幾乎沒有，除過是在骨細胞中，因為骨細胞中的紅細胞（應該就是造血干細胞）仍在分裂生長 ，除此之外，癌細胞中的T也有，因為癌細胞分裂的rapidly，最后問能推出什么，我選的是說如果成年人骨中發現T不是癌癥的indication。這個選項的對錯不保證，我還猶豫了一 會兒，有幾個選項好像是在fast和rapidly上做文章的，大家到時留意 C
Telomerase is an enzyme that is produced only in cells that are actively dividing. For this reason it is generally absent from body tissues in adults. Bone marrow is an exception to this rule, however, since even in adults, bone marrow cells continually divide to replace old blood cells. Cancers are another exception, because their cells are rapidly dividing.
The information provided most strongly supports which of the following?
A.Telomerase is the only enzyme that is present in cancerous cells but absent from cells that are not actively dividing.
B.In children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing.
C.The presence of telomerase in bone marrow is no indication of bone marrow cancer.
D.Cancer of the bone marrow develops more rapidly than cancer growing in any other kind of adult tissue.
E.The level of telomerase production is always higher in cancerous tissue than in noncancerous tissue
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发表于 2009-1-4 12:14:00
