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  3. Previously, the sack-like rabbit appendix was thought to serve primaril

Previously, the sack-like rabbit appendix was thought to serve primaril

游客2024-01-11  62
问题          Previously, the sack-like rabbit appendix was thought to serve primarily as
     a reservoir for the bacteria involved in hindgut fermentation, a explanation
     that failed to account for the absence of an appendix in other animals with
     similar digestive systems or for its presence in humans. Microscopic research
(5)   revealed that the appendix contains a significant amount of lymphoid tissue,
     similar aggregates of which tissue occur in other areas of the gastrointestinal
     tract. These are involved, possibly, in the body’s ability to recognize foreign
     antigens in ingested material, but the evidence is inconclusive, to the extent
     that scientists have long discounted the human appendix as a "vestigial" organ.
(10)  However, a growing body of evidence suggests that the appendix, far from
     being a "vestigial organ", hag a significant function as a part of the body’ s
     immune system. The appendix achieves its greatest development shortly after
     birth, when immune response is first developing, then regresses with age,
     when the immune response mediated by the appendix may relate to such
(15)  inflammatory conditions as ulcerative colitis, which in adults necessitates the
     organ’ s surgical removal.
选项 A、After laboratory experiments, scientists discover evidence to reject the notion hat the human appendix is a "vestigial" organ.
B、Certain animal species which had not previously been given attention are to possess an appendix resembling that of humans.
C、Lymphoid tissue is discovered, after careful study, not to play a role in the recognition of foreign antigens in ingested material.
D、After re-examination of the evidence, ulcerative colitis is discovered to be caused by factors wholly unrelated to the human appendix.
E、It is discovered that in rabbits, hindgut fermentation does not require the presence of an organ acting as reservoir for bacteria.
答案 A
解析
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