阅读理解　　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 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. 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 inflammatory conditions as ulcerative colitis, which in adults necessitates the organ'' s surgical removal.

单选题 Which of the following hypothetical discoveries, if made, would cast MOST doubt on the most recent conclusions regarding the function of the human appendix?

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.

单选题 Which of the following best describes the relationship of the second paragraph to the first?

A、 The second paragraph relies on different evidence in drawing a conclusion similar to that expressed in the first paragraph.
B、 The second paragraph provides further elaboration on why an assertion made at the end of the first paragraph proves true in most cases.
C、 The second paragraph provides additional information in support of a hypothesis stated in the first paragraph.
D、 The second paragraph provides an example of a case in which the assumption described in the first paragraph is unwarranted.
E、 The second paragraph describes a phenomenon that has the same cause as the phenomenon described in the first paragraph.

单选题 It can be inferred from the passage that the author of the passage would be most likely to agree with which of the following assertions about the appendix?

A、 Scientists have ruled out the possibility that the appendix is involved in hindgut fermentation in all species, including rabbits.
B、 As an organ, the appendix is more useful to the immune response of human beings in their first development than later in life.
C、 The human appendix contains greater amounts of lymphoid tissue than the aggregates of which that are found in other areas of the gastrointestinal tract.
D、 The appendix in a human child is generally less well developed than the appendix in a human adult.
E、 The presence of the appendix in humans suggests that the human digestive process resembles the rabbit digestive process more than that of other animal species.

单选题 The passage provides information in support of which of the following assertions?

A、 Lymphoid tissue somehow involved in the body''s ability to recognize foreignantigens in ingested material is a primary cause of ulcerative colitis.
B、 The appendix is an anomaly among mammals, existing in rabbits and humans largely as an evolutionary fluke.
C、 Microscopic research is insufficient to give even the vaguest suggestion of what the human appendix''s function may be.
D、 The digestive process in human beings is less dependent on the hindgut fermentation process than is the digestive process in rabbits.
E、 Lymphoid tissue that recognize foreign antigens is absent in the digestive systems of animals that lack appendixes.