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Microbiologist: Because heavy metals are normally concentrated in

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Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 24 Aug 2017, 10:54
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A
B
C
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E

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  65% (hard)

Question Stats:

60% (02:08) correct 40% (02:11) wrong based on 210 sessions

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Microbiologist: Because heavy metals are normally concentrated in sewage sludge during the sewage treatment process, the bacteria that survive in the sludge have evolved the unusual ability to resist heavy-metal poisoning. The same bacteria also show a strong resistance to antibiotics. This suggests that the bacteria’s exposure to the heavy metals in the sewage sludge has somehow promoted their resistance to antibiotics.

Which one of the following, if true, most strengthens the microbiologist’s argument?

(A) Most bacteria that are not resistant to antibiotics are not resistant to heavy-metal poisoning either.
(B) Bacteria that live in sewage sludge that is free of heavy metals, but is in other respects similar to normal sewage, are generally resistant to neither heavy-metal poisoning nor antibiotics.
(C) Antibiotic resistance of bacteria that survive in sewage sludge in which heavy metals are concentrated contributes to their resistance to heavy-metal poisoning.
(D) Sewage sludge that contains high concentrations of heavy metals almost always contains significant concentrations of antibiotics.
(E) Many kinds of bacteria that do not live in sewage sludge are resistant to both heavy-metal poisoning and antibiotics.

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Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 02 Apr 2019, 20:37
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Shef08 wrote:
Someone please explain why not C?

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Option C states "Antibiotic resistance of bacteria that survive in sewage sludge in which heavy metals are concentrated contributes to their resistance to heavy-metal poisoning", which mean Antibiotic resistance property contributes bacteria resistance to heavy-metal poisoning. But this doesn't strengthen our argument because we are not sure whether antibiotic resistance property actually contributes bacteria resistance to heavy-metal poisoning or not.
Correct answer is we need our argument to strengthen by stating that Bacteria that live in sewage sludge that is free of heavy metal are generally resistant to neither heavy-metal poisoning nor antibiotics, which implies bacteria’s exposure to the heavy metals in the sewage sludge has somehow promoted their resistance to antibiotics and heavy-metal poisoning.

Answer option B is correct.
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Re: Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 24 Aug 2017, 11:07
2.48 minutes!! Still too slow... although picked the correct one. :)
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Re: Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 24 Aug 2017, 11:49
+1 for B. The others don't strongly indicate a "causal relationship" between the presence of metals and antibiotics. Only B does so. It does so by eliminating the possibility of the effect occuring without the occurence of the cause.

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Re: Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 25 Aug 2017, 04:08
Masshole wrote:
Microbiologist: Because heavy metals are normally concentrated in sewage sludge during the sewage treatment process, the bacteria that survive in the sludge have evolved the unusual ability to resist heavy-metal poisoning. The same bacteria also show a strong resistance to antibiotics. This suggests that the bacteria’s exposure to the heavy metals in the sewage sludge has somehow promoted their resistance to antibiotics.

Which one of the following, if true, most strengthens the microbiologist’s argument?

(A) Most bacteria that are not resistant to antibiotics are not resistant to heavy-metal poisoning either.
(B) Bacteria that live in sewage sludge that is free of heavy metals, but is in other respects similar to normal sewage, are generally resistant to neither heavy-metal poisoning nor antibiotics.
(C) Antibiotic resistance of bacteria that survive in sewage sludge in which heavy metals are concentrated contributes to their resistance to heavy-metal poisoning.
(D) Sewage sludge that contains high concentrations of heavy metals almost always contains significant concentrations of antibiotics.
(E) Many kinds of bacteria that do not live in sewage sludge are resistant to both heavy-metal poisoning and antibiotics.

LSAT



+1 For B. Bacterial exposed to heavy metals>resistant to antibiotics. B says-Bacteria not exposed to heavy metals>not resistant to antibiotics.
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Re: Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 02 Apr 2019, 13:29
Bumping for discussion. A really fun LSAT question that should be discussed a little more.
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Re: Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 02 Apr 2019, 19:07
Someone please explain why not C?

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Re: Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 03 Apr 2019, 01:18
Hi,

Can anybody explain why A is incorrect?
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Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 03 Apr 2019, 04:47
Microbiologist: Because heavy metals are normally concentrated in sewage sludge during the sewage treatment process, the bacteria that survive in the sludge have evolved the unusual ability to resist heavy-metal poisoning. The same bacteria also show a strong resistance to antibiotics. This suggests that the bacteria’s exposure to the heavy metals in the sewage sludge has somehow promoted their resistance to antibiotics.

Premise: Heavy metals are normally concentrated in sewage sludge during the sewage treatment process
Premise: The bacteria that survive in the sludge have evolved the unusual ability to resist heavy-metal poisoning
Premise: The same bacteria also show a strong resistance to antibiotic
Conclusion: This suggests that the bacteria’s exposure to the heavy metals in the sewage sludge has somehow promoted their resistance to antibiotics

-- Fairly straightforward question, in terms of set up. We just want show that either the heavy metals caused the antibiotic resistance, or that there is something that can strengthen this connection. My initial thought, which ended up correct, was that the answer was going to show how one caused the other.



Which one of the following, if true, most strengthens the microbiologist’s argument?

(A) Most bacteria that are not resistant to antibiotics are not resistant to heavy-metal poisoning either. -- This is incorrect because we do not know which caused the other. It could very well be that the antibiotic resistance caused the metal poisoning resistance. Do not assume anything!

(B) Bacteria that live in sewage sludge that is free of heavy metals, but is in other respects similar to normal sewage, are generally resistant to neither heavy-metal poisoning nor antibiotics. -- Perfect! So in the absence of the metal, we are told that the bacteria no longer has either; this means that the metal is the cause of both and thus is our answer.

(C) Antibiotic resistance of bacteria that survive in sewage sludge in which heavy metals are concentrated contributes to their resistance to heavy-metal poisoning. -- This says the opposite of what we want. This says the antibiotics cause the metal resistance. Classic trap answer.

(D) Sewage sludge that contains high concentrations of heavy metals almost always contains significant concentrations of antibiotics. -- And? So we are told that there are a few key elements, but we once more have no idea how these affect our bacteria, or the cause. We would have to assume a few things and then make the same assumption we did in (A) just to make this work.

(E) Many kinds of bacteria that do not live in sewage sludge are resistant to both heavy-metal poisoning and antibiotics. -- Cool, but who cares? We want to know about those that DO live in the sludge and are resistant to both. So this is out.
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Re: Microbiologist: Because heavy metals are normally concentrated in  [#permalink]

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New post 03 Apr 2019, 05:34
Akela wrote:
Microbiologist: Because heavy metals are normally concentrated in sewage sludge during the sewage treatment process, the bacteria that survive in the sludge have evolved the unusual ability to resist heavy-metal poisoning. The same bacteria also show a strong resistance to antibiotics. This suggests that the bacteria’s exposure to the heavy metals in the sewage sludge has somehow promoted their resistance to antibiotics.

Which one of the following, if true, most strengthens the microbiologist’s argument?

(A) Most bacteria that are not resistant to antibiotics are not resistant to heavy-metal poisoning either.
(B) Bacteria that live in sewage sludge that is free of heavy metals, but is in other respects similar to normal sewage, are generally resistant to neither heavy-metal poisoning nor antibiotics.
(C) Antibiotic resistance of bacteria that survive in sewage sludge in which heavy metals are concentrated contributes to their resistance to heavy-metal poisoning.
(D) Sewage sludge that contains high concentrations of heavy metals almost always contains significant concentrations of antibiotics.
(E) Many kinds of bacteria that do not live in sewage sludge are resistant to both heavy-metal poisoning and antibiotics.

LSAT


Certainly an engaging question. A single read of the options was not enough and I did come back to review the options again before choosing (B)!

Sewage sludge has heavy metals.
Bacteria that survive in it are resistant to heavy metals.
Same bacteria also show a strong resistance to antibiotics

Conclusion: Bacteria’s exposure to the heavy metals in the sewage sludge has promoted their resistance to antibiotics.

We need to strengthen that heavy metals in the sludge has led to antibiotic resistance.
Exposure to Heavy metals in sludge (cause) -> Resistance to antibiotics (effect)

(A) Most bacteria that are not resistant to antibiotics are not resistant to heavy-metal poisoning either.

We have to establish that exposure to heavy metals leads to resistance to antibiotics.
The fact that 'no resistance to antibiotics' and 'no resistance to heavy metal poisoning' co-exist doesn't help in establishing that heavy metals resistance leads to antibiotic resistance. It might show that there may be a relation between 'resistance to antibiotics' and 'resistance to heavy metal poisoning' but it does not show that 'resistance to heavy metal poisoning' is the cause of 'resistance to antibiotics'.

(B) Bacteria that live in sewage sludge that is free of heavy metals, but is in other respects similar to normal sewage, are generally resistant to neither heavy-metal poisoning nor antibiotics.

Imp point here - Bacteria that live is sewage sludge similar to this one but without heavy metals. So the distinction is heavy metals. These bacteria are not resistant to antibiotics. Then it does seem that resistance to heavy metals is the cause of resistance to antibiotics. It does strengthen our conclusion.

(C) Antibiotic resistance of bacteria that survive in sewage sludge in which heavy metals are concentrated contributes to their resistance to heavy-metal poisoning.

Incorrect. This establishes the opposite relation - that 'antibiotic resistance' causes 'resistance to heavy-metal poisoning'. Our conclusion establishes the opposite relation.

(D) Sewage sludge that contains high concentrations of heavy metals almost always contains significant concentrations of antibiotics.

Irrelevant. If anything, it may weaken our conclusion. If presence of heavy metals and presence of antibiotics happens together, it may be that the bacteria are developing resistance of antibiotics because they are exposed to them. Then heavy metal resistance may not be leading to antibiotic resistance.

(E) Many kinds of bacteria that do not live in sewage sludge are resistant to both heavy-metal poisoning and antibiotics.

Doesn't help. We don't know what is the cause and what is the effect. It just tells us that the two co-exist. Doesn't help our conclusion that 'resistance to heavy metal poisoning' is the cause of 'resistance to antibiotics'.

Answer (B)
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Re: Microbiologist: Because heavy metals are normally concentrated in   [#permalink] 03 Apr 2019, 05:34
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