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655-705 (Hard)|   Assumption|      
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Human skin gives off an array of gaseous substances, including carbon Updated on: 16 Jul 2018, 23:32
Originally posted by LeoGT on 16 Jul 2018, 23:24.
Last edited by Bunuel on 16 Jul 2018, 23:32, edited 1 time in total.
Renamed the topic and edited the question.
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B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

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65% (01:51) correct 35% (02:01) wrong based on 891 sessions

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Human skin gives off an array of gaseous substances, including carbon dioxide and lactic acid, both of which attract mosquitoes. However, neither of these two substances, whether alone or combined with one another, will attract mosquitoes as much as a bare human arm will, even in complete darkness, where a mosquito has no visual cues. Therefore, some other gaseous substance given off by human skin also attracts mosquitoes.

The reasoning in the argument requires which one of the following assumptions?

(A) Mosquitoes do not communicate with one another.
(B) Mosquitoes are not attracted to humans by body heat.
(C) Human skin gives off gaseous substances in greater amounts during the day than during the night.
(D) Mosquitoes are no more successful in finding a bare human arm in darkness than in light.
(E) Human skin never gives off any gaseous substances that repel mosquitoes.
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B
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Human skin gives off an array of gaseous substances, including carbon 17 Jul 2018, 00:29
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Premise

Human skin gives off gaseous substances, two of which attract mosquitos. However, neither substance attracts mosquitoes as much as a bare human arm does.

Conclusion

Some gaseous substance, given off by the human skin, other the two mentioned also attracts mosquitoes.

Assumption

Helps bridge the gap between the conclusion and premise in the context of the information provided.

LeoGT
Human skin gives off an array of gaseous substances, including carbon dioxide and lactic acid, both of which attract mosquitoes. However, neither of these two substances, whether alone or combined with one another, will attract mosquitoes as much as a bare human arm will, even in complete darkness, where a mosquito has no visual cues. Therefore, some other gaseous substance given off by human skin also attracts mosquitoes.

The reasoning in the argument requires which one of the following assumptions?

(A) Mosquitoes do not communicate with one another.
Since we can't fit in this answer choice as a valid assumption, this is incorrect.
(B) Mosquitoes are not attracted to humans by body heat.
This answer choice makes sure there is no other cause of attraction for the mosquito towards a human. Therefore gaseous substance may be the only reason. Sufficient to bridge the gap between the conclusion and premise.
(C) Human skin gives off gaseous substances in greater amounts during the day than during the night.
Had amounts been greater during the night, both parts [skin and arm] would attract equally well during the day. Which is something the conclusion is not concerned with.
(D) Mosquitoes are no more successful in finding a bare human arm in darkness than in light.
Does not bridge the gap between the conclusion and the premise. Can't be a valid assumption.
(E) Human skin never gives off any gaseous substances that repel mosquitoes.
Mosquitoes which are repelled by the human skin are out of context. There may be some, (we don't know) question takes into account only those mosquitoes which are attracted to humans - bare hand or skin.
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Correct Answer:B


I'm open to criticism, let me know if my reasoning is flawed.

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Human skin gives off an array of gaseous substances, including carbon 17 Jul 2018, 07:48
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abhinav770

Premise

Human skin gives off gaseous substances, two of which attract mosquitos. However, neither substance attracts mosquitoes as much as a bare human arm does.

Conclusion

Some gaseous substance, given off by the human skin, other the two mentioned also attracts mosquitoes.

Assumption

Helps bridge the gap between the conclusion and premise in the context of the information provided.

LeoGT
Human skin gives off an array of gaseous substances, including carbon dioxide and lactic acid, both of which attract mosquitoes. However, neither of these two substances, whether alone or combined with one another, will attract mosquitoes as much as a bare human arm will, even in complete darkness, where a mosquito has no visual cues. Therefore, some other gaseous substance given off by human skin also attracts mosquitoes.

The reasoning in the argument requires which one of the following assumptions?

(A) Mosquitoes do not communicate with one another.
Since we can't fit in this answer choice as a valid assumption, this is incorrect.
(B) Mosquitoes are not attracted to humans by body heat.
This answer choice makes sure there is no other cause of attraction for the mosquito towards a human. Therefore gaseous substance may be the only reason. Sufficient to bridge the gap between the conclusion and premise.
(C) Human skin gives off gaseous substances in greater amounts during the day than during the night.
Had amounts been greater during the night, both parts [skin and arm] would attract equally well during the day. Which is something the conclusion is not concerned with.
(D) Mosquitoes are no more successful in finding a bare human arm in darkness than in light.
Does not bridge the gap between the conclusion and the premise. Can't be a valid assumption.
(E) Human skin never gives off any gaseous substances that repel mosquitoes.
Mosquitoes which are repelled by the human skin are out of context. There may be some, (we don't know) question takes into account only those mosquitoes which are attracted to humans - bare hand or skin.

Correct Answer:B


I'm open to criticism, let me know if my reasoning is flawed.

If this helped, how about sending some Kudos my way? :-)
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Since body heat is not mentioned ..how come option B.

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Human skin gives off an array of gaseous substances, including carbon 17 Jul 2018, 08:06
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Assumption negation technique:
Negate the contender and see whether the argument is sustained or collapsed.

Negate B ...
Mosquitoes are attracted to humans by body heat.

So except gaseous substances, body heat is also cause of attracting mosquito.
Therefore, B is correct answer.
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Human skin gives off an array of gaseous substances, including carbon 17 Jul 2018, 08:25
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Hey vineethk929! Thanks for the query.

If answer choice (B) is correct, then a mosquito bite is not dependent on body heat, hence the only other factor behind mosquito's attraction toward human skin or arm must be gaseous substances given off from the body. To conclude the conclusion mentioned below, this was a fact assumed to be true. Although this information is not mentioned in the passage it sufficiently fills the gap between the conclusion and the premise. Hence it should be the correct answer.

Cheers! :-)

vineethk929
abhinav770

Premise

Human skin gives off gaseous substances, two of which attract mosquitos. However, neither substance attracts mosquitoes as much as a bare human arm does.

Conclusion

Some gaseous substance, given off by the human skin, other the two mentioned also attracts mosquitoes.

Assumption

Helps bridge the gap between the conclusion and premise in the context of the information provided.

LeoGT
Human skin gives off an array of gaseous substances, including carbon dioxide and lactic acid, both of which attract mosquitoes. However, neither of these two substances, whether alone or combined with one another, will attract mosquitoes as much as a bare human arm will, even in complete darkness, where a mosquito has no visual cues. Therefore, some other gaseous substance given off by human skin also attracts mosquitoes.

The reasoning in the argument requires which one of the following assumptions?

(A) Mosquitoes do not communicate with one another.
Since we can't fit in this answer choice as a valid assumption, this is incorrect.
(B) Mosquitoes are not attracted to humans by body heat.
This answer choice makes sure there is no other cause of attraction for the mosquito towards a human. Therefore gaseous substance may be the only reason. Sufficient to bridge the gap between the conclusion and premise.
(C) Human skin gives off gaseous substances in greater amounts during the day than during the night.
Had amounts been greater during the night, both parts [skin and arm] would attract equally well during the day. Which is something the conclusion is not concerned with.
(D) Mosquitoes are no more successful in finding a bare human arm in darkness than in light.
Does not bridge the gap between the conclusion and the premise. Can't be a valid assumption.
(E) Human skin never gives off any gaseous substances that repel mosquitoes.
Mosquitoes which are repelled by the human skin are out of context. There may be some, (we don't know) question takes into account only those mosquitoes which are attracted to humans - bare hand or skin.

Correct Answer:B


I'm open to criticism, let me know if my reasoning is flawed.

If this helped, how about sending some Kudos my way? :-)
Since body heat is not mentioned ..how come option B.

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Human skin gives off an array of gaseous substances, including carbon 01 Nov 2023, 05:47
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I eliminated (B) because the argument doesn't mention that gaseous substances given off the the human skin/arm are the ONLY possible way to attract mosquitoes. The conclusion mentions that there is an ancillary factor that draws mosquitoes to the human body.
Even if mosquitoes are attracted to human body by other gaseous substances, they could still be attracted to the human body by body heat.

Could an expert please give his or her POV on B, D, and E.
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Human skin gives off an array of gaseous substances, including carbon 01 Nov 2023, 10:05
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I eliminated (B) because the argument doesn't mention that gaseous substances given off the the human skin/arm are the ONLY possible way to attract mosquitoes. The conclusion mentions that there is an ancillary factor that draws mosquitoes to the human body.
Even if mosquitoes are attracted to human body by other gaseous substances, they could still be attracted to the human body by body heat.

Could an expert please give his or her POV on B, D, and E.
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Here's an explanation for the question.

Human skin gives off an array of gaseous substances, including carbon dioxide and lactic acid, both of which attract mosquitoes. However, neither of these two substances, whether alone or combined with one another, will attract mosquitoes as much as a bare human arm will, even in complete darkness, where a mosquito has no visual cues. Therefore, some other gaseous substance given off by human skin also attracts mosquitoes.

The conclusion of the argument is the following:

    some other gaseous substance given off by human skin also attracts mosquitoes

The support for the conclusion is this premise:

    neither of these two substances (carbon dioxide and lactic acid), whether alone or combined with one another, will attract mosquitoes as much as a bare human arm will, even in complete darkness, where a mosquito has no visual cues

We see that the author has reasoned that, since a human arm in darkness attracts mosquitoes more than carbon dioxide and lactic acid do, some gaseous substance in addition to carbon dioxide and lactic acid must be given off by the human arm.

The reasoning in the argument requires which one of the following assumptions?

The correct answer is an assumption that the author must make in order for the premise to support the conclusion.

(A) Mosquitoes do not communicate with one another.

The argument still works even if this choice isn't true. After all, even if mosquitoes do communicate with one another, they could still be more attracted to human skin than to carbon dioxide and lactic acid because human skin gives off other gaseous substance.

Eliminate.

(B) Mosquitoes are not attracted to humans by body heat.

In the argument, the author goes from the fact that a human arm in darkness attracts mosquitoes more than carbon dioxide and lactic acid to the conclusion that some other gaseous substance given off by human skin also attracts mosquitoes.

In going from that evidence to that conclusion, the author has made the general assumption that there is not something other than gaseous substances that could be attracting mosquitoes to human skin. After all, if something other than gaseous substances attracts mosquitoes, then the conclusion doesn't follow from the evidence since it's doesn't have to be the case that some other gaseous substance attracts mosquitoes if there is something else that attracts mosquitoes to human skin.

One example of something else that could attract mosquitoes is body heat. If body heat attracts mosquitoes, then it doesn't have to be the case that some other gaseous substance that attracts mosquitoes is given off by human skin. Rather, it could be the case that the reason a human arm in darkness attracts mosquitoes more than carbon dioxide and lactic acid is that a human arm gives off heat.

So, the argument requires the assumption that "Mosquitoes are not attracted to humans by body heat."

Keep.

(C) Human skin gives off gaseous substances in greater amounts during the day than during the night.

The argument doesn't require assuming any difference between what human skin does during the day and what human skin does during the night. Darkness is mentioned in the argument only to show that mosquitoes are not using vision to find human skin, and regardless of any comparison between what human skin does during the day and what human skin does during the night, it still follows that, if mosquitoes cannot see the arm, then they must be going to it for some other reason, such as that they are attracted by gaseous substances.

Eliminate.

(D) Mosquitoes are no more successful in finding a bare human arm in darkness than in light.

Notice that, even if this choice is not true, and mosquitoes ARE more successful in finding a bare human arm in darkness than in light, there is still some reason why they are attracted to a human arm in darkness.

So, the argument works even if this choice is not true.

Eliminate.

(E) Human skin never gives off any gaseous substances that repel mosquitoes.

Even if human skin DOES sometimes give off gaseous substances that repel mosquitoes, the fact that mosquitoes are more attracted to a human arm than to carbon dioxide and lactic acid still supports the conclusion of the argument. After all, something is causing mosquitoes to be attracted to a human arm.

Eliminate.

The correct answer is (B).
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Human skin gives off an array of gaseous substances, including carbon 04 Jan 2026, 18:53
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