Macrophages are cells that play a role in the response of the immune s

Question

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.

arhumsid · Accepted Answer

At first B seemed a contender, then realized its wayyy out of scope-
 B. Mice that show elevated levels of nitrates can easily fight off most types of bacterial infections.

We only have these connections given to us:
i.  Macrophages and Bacteria  (Macrophages help immune system to fight against bacteria)
ii.  Macrophages and Nitrates' level  (no Macrophages, no high Nitrates)

While option C correctly explains 'ii' above, option B brings in a new and incorrect relationship:
Nitrates and Bacteria. (wrong because its Macrophages that fight bacteria and not the Nitrates)

anandsebastin · Answer

Clear  C  for me. 
The conclusion is more about the nitrate production than about the defense mechanisms against bacterial infections. 
No macrophage = no nitrate. C states that macrophages are involved in production of nitrates (positive role) or inhibition of nitrate break down (negative role).

gmat_stuff · Answer

C.

I thought B was close too, I eliminated B because it uses "fight off  most  types of bacterial infections", which is extreme. 

There was one more thing that bothered me, argument says "macrophages" plays role in providing immune system against bacterial infection, so nitrate level could just be a side effect and that doesn't mean when you high level of nitrate level, it can make "macrophages"

RaviChandra · Answer

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.

Kindly provide your answer and reason for eliminating other answer choices

rajatmahan · Answer

I will go for C. As it seems to be Cause and Effect kind of relationship. In the 2nd line it is mentioned that "mice which are incapable of making Macrophages cells do not show elevated levels of Nitrates when infected with Bacteria." So bacteria doesnot cause the nitrate levels thus the macrophages are responsible in the production of nitrates. Thus will go with C.

KrishnakumarKA1 · Answer

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.( Wrong Answer : Nothing is there in the argument that supports this type of conclusion.)

B:Mice that show elevated levels of nitrates can easily fight off most types of bacterial infections.( Wrong Answer : This sort of connection between elevated levels of nitrates and bacterial infections is not reflected in the argument.)

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.( Correct Answer : The last line of the argument i,e Unlike …………….bacteria points to this kind of a role played by macrophages )

D:When a healthy mouse becomes infected with an invasive organism, the number of macrophages in the mouse body decreases.( Wrong Answer : This is nowhere indicated in the argument.)

E:Injections of nitrates into mice that lack macrophages will not enhance the ability of these animals immune systems to fight off infection.(Wrong Answer : This is out of scope of the argument.)

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NNURP · Answer

Here are some of my takes, please correct me if I am wrong.

Q: The statements above, if true, provide the most support for which of the following conclusions?
-From the passage, we know that Macrophages will fight off bacteria. However, mice without Macrophages will not shown elevate level of nitrate when infected. In short, when Macrophages fight off bacteria the nitrate level will elevate. But we do not know which cause which and what really kills bacteria(i.e. either Macrophages produce nitrate to fight off bacteria OR nitrates can be the wastes after Macrophages fights off bacteria). What we know is the Macrophages is something to do with the level of nitrates and Macrophages fight off bacteria.

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.
-Wrong. Out of scope. We are not discussing "some other way" of the immune system.

B:Mice that show elevated levels of nitrates can easily fight off most types of bacterial infections.
-Wrong. From the passage, we only know that Macrophages fight off the bacteria and linked with the level of nitrates. (or maybe nitrates just the wastes after Macrophages fight off bacteria.)

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.
-Correct Answer. Macrophages linked with level of nitrates. This choice clearly explains that Macrophages plays a role in the production with nitrate.

D:When a healthy mouse becomes infected with an invasive organism, the number of macrophages in the mouseâ€™s body decreases.
-Wrong. Out of scope. Passage does not mention the relationship between total number of Macrophages and bacteria.

E:Injections of nitrates into mice that lack macrophages will not enhance the ability of these animalsâ€™ immune systems to fight off infection.
-Wrong. Same as choice B, we do not know the the exact role of nitrates in this defensive mechanism.

gmatexam439 · Answer

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. - We don't know whether such mice will be able to defend themselves.

(B) Mice that show elevated levels of nitrates can easily fight off most types of bacterial infections. - We don't know this. Maybe the nitrate levels increased because of something else.

(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. - Correct. Macrophages maybe one source of nitrate's generation in mice.

(D) When a healthy mouse becomes infected with an invasive organism, the number of macrophages in the mouse’s body decreases. - Don't know

(E) Injections of nitrates into mice that lack macrophages will not enhance the ability of these animals’ immune systems to fight off infection. - Don't know

akshaypandey · Answer

I'm struggling to understand why C is the correct choice. Can someone please explain how it links to the argument?

MartyTargetTestPrep · Answer

The correct answer must be a conclusion supported by the statements in the passage.

The passage tells us two things.

- Macrophages play a role in the RESPONSE to infection by bacteria. In other words, when mice are infected, the macrophages act.

- UNLIKE OTHER MICE, mice that are genetically incapable of making these particular cells, in other words, mice that DO NOT HAVE MACROPHAGES, do not show elevated levels of nitrates when infected with bacteria.

That statement also implies that mice that DO HAVE MACROPHAGES do have elevated levels of nitrates when they are infected.

Now, here's choice (C).

(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.

We can see that choice (C) is supported by the statements in the passage since the passage indicates that, when macrophages ARE NOT present, mice DO NOT show elevated levels of nitrates when infected, and when macrophages ARE present, the mice DO show elevated levels of nitrates when infected.

So, it follows that macrophages either help with production of nitrates or keep nitrates from leaving the mice because those are the two ways in which nitrate levels would become elevated as a result of the presence of macrophages.

Now, it's true that the passage does not PROVE that (C) is correct. It could be the case that (C) is not true even though the statements in the passage are true. All the same, (C) is a conclusion that is at least supported by the statements in the passage.

MishraB2 · Answer

Dear Experts,

Could you please explain the role of the mentioned phrase (or otherwise eliminated) in the correct answer choice.

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

Thanks

guddo · Answer

Normal mice show elevated nitrate levels when infected with bacteria. Mice genetically unable to make macrophages do not show this nitrate increase during infection.

The observed difference directly ties the presence of macrophages to elevated nitrate levels during infection. This supports the conclusion that macrophages are involved in either producing nitrates or preventing their removal.

Option (C) states this precisely.

The other options introduce unsupported claims about alternative protection methods (A), the effect of nitrates on fighting infections (B), changes in macrophage numbers (D), or the impact of injecting nitrates (E).

Answer: (C)

guddo · Answer

I think the phrase "or otherwise eliminated" is in there to make sure the explanation covers all the bases.

In the study, mice with macrophages show higher nitrate levels when infected. That could happen two ways: either macrophages help  create  more nitrates, or they  slow down the removal  of nitrates.

"Broken down" means chemical decomposition. But nitrates could also leave the body through other paths, like being filtered out by the kidneys and excreted in urine. If macrophages were blocking that excretion, nitrate levels would also rise.

So "or otherwise eliminated" just wraps up any other way nitrates might leave the system. It makes the conclusion complete and precise.

Macrophages are cells that play a role in the response of the immune s

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Macrophages are cells that play a role in the response of the immune s

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