T-3-23; GWD-13-32

白流苏

T-3-Q23. GWD-13-32

Macrophages are cells that play a role in the response of the immune system of mice and other mammals to invasive organisms such as bacteria. Unlike other mice, mice that are genetically incapable of making these particular cells do not show elevated levels of nitrates when infected with bacteria.

The statements above, if true, provide the most support for which of the following conclusions?

 

 

1. Mice that are unable either to make macrophages or to make them in sufficient numbers will protect themselves from bacterial infections in some other way.

2. Mice that show elevated levels of nitrates can easily fight off most types of bacterial infections.

3. In mice, macrophages play a role in the production of nitrates or inhibit a process by which nitrates are broken down or otherwise eliminated.

4. When a healthy mouse becomes infected with an invasive organism, the number of macrophages in the mouse’s body decreases.

5. Injections of nitrates into mice that lack macrophages will not enhance the ability of these animals’ immune systems to fight off infection.

选C,

前提：M跟老鼠抵抗病菌的免疫系统有关。

结论：没有M的老鼠，受到病菌感染的时候，N比较低。

B：有N的老鼠，可以轻易抵抗病菌感染

C：M跟N的产生过程及制约破坏N的机制有关

 

 

B错误在于play a role 不代表fight off, 超出文章范围；

 

 

问：

C只address到了结论，和前提没什么关系。

如果把B改成N play a role in immune system in dealing with bacteria是不是更好？

 P. S. I felt there should be some connection between the premise and the conclusion,  therefore predicted that the correct answer should be linking nitrates and Macrophage.....Anyway, can't find an answer better than C.

 

[此贴子已经被作者于2008-8-6 13:18:07编辑过]

gracetin

本題根據題幹所提供的資訊來得出適合的結論

所以不可以超出題幹所提供的資訊

題幹：

invasive organisms =>Macrophages

某些mice(無法產生Macrophages )於此情況下=>do not show elevated levels of nitrates

根據以上我們只可以知道  Macrophages 對nitrates的數量有正面影響

文中沒有表明elevated levels of nitrates跟病毒入侵有任何關係

下結論的題目必須完全follow文中資訊

應該避免推測 所以我覺得 就算把(B)的較為委婉 (C)仍然是最佳選項

dhdlorent

in B, fight off most types of bacterial infections is 扩大推理.

"Unlike other mice, mice that are genetically incapable of making these particular cells do not show elevated levels of nitrates when infected with bacteria." ===>

mice capable of making M......show elevated levels of N, when infected with bacteria.

since M is to fight off bacteria, and bacteria is associated with N's elevation, M defintely play a role in either increasing N or preventing N from decrease.

so, C is the right key

白流苏

恍然大悟...~~