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Bacteria in Mice

Expert replies
by student22 » Fri May 28, 2010 5:59 pm
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?

A. 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.
B. Mice that show elevated levels of nitrates can easily fight off most types of bacterial infections.
C. In mice, macrophages play a role in the production of nitrates or inhibit a process by which nitrates are broken down or otherwise eliminated.
D. When a healthy mouse becomes infected with an invasive organism, the number of macrophages in the mouse’s body decreases.
E. Injections of nitrates into mice that lack macrophages will not enhance the ability of these animals’ immune systems to fight off infection.


OA: C

My question is, why does the argument assume that macrophages regulate nitrates. Since there's no definition of nitrates given, I thought that the answer is A. I thought that nitrates are signatures given off by bacteria infections. Kind of like protein signatures given off by viruses.
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Source: — Critical Reasoning |

by pradeepkaushal9518 » Fri May 28, 2010 8:20 pm
it is clear from the arugment that
conclusions

1. macrophages are most import part in immune system
2.more macrophages cells means elevated level of nitrates,less macrophages means less nitrates levels.

means if macrophages controls the level of nitrates is true then the above conclusions will be true.

and the same statement is written in option C which supports the argument

i hope its clear now
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by student22 » Sat May 29, 2010 7:10 am
This is the part I'm not clear about. Which words in the question tell you that the macrophages control nitrate levels instead of the bacteria causing nitrate levels to go up or down. Because the way I'm reading it, it can be interpreted either way.
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by pradeepkaushal9518 » Sat May 29, 2010 9:40 am
"Unlike other mice, mice that are genetically incapable of making these particular cells do not show elevated levels of nitrates when infected with bacteria. "

this above line clearly says that mice incapable of making these particular cells( macrophages) do not show elevated levels of nitrates ( means low cells low nitrates) when infected with bacteria. if no bacteria then more cells hence elevated levels of nitrates

i hope it is clear to you
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by student22 » Sat May 29, 2010 12:22 pm
Yeah, I it makes sense. I guess I was reading too much into it. Thanks pradeepkaushal9518, for explaining it!
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