gwd13-32 v

Q32:

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.

   Answer:

key is c , but i choose b

一个归纳题！明显有公共元素Macrophages ！前半讲Macrophages 与免疫系统的关系，后半讲Macrophages 与nitrates的关系！b项很明显搭建了免疫系统和nitrates的关系！

我觉得b更好些！

看了以前的讨论，结果不明！请高人指点！

答案C没错。

原文可以推断出的结论是michrophages与nitrate有关联，即C。至于B，nitrate可以抵抗感染，就完全是你自己的推断了，你不能从原文找出根据。Nitrate可以是细菌被microphages杀死后的副产品，也可能是michrophages被杀死的产物。我们找不到任何关于nitrate可以抵抗细菌的依据。

同意精神自由mindfree的说法。

文中只说巨噬细胞在免疫系统对细菌入侵中起作用，并没说起多大作用。