Human skin gives off an array

Answer choices

1. A

   Out of Scope / Irrelevant1% picked this

   Mosquitoes do not communicate with one

   When answer choices on Necessary Assumption use "not" to rule out an idea, that's very attractive to us. We should negate it to see whether it weakens. If "mosquitoes can communicate with one another" would that weaken the argument? Is that a different explanation for why they like human arms more than just those two gases? No. If mosquitoes can communicate with one another, does that disrupt the author's storyline that mosquitoes like at least a third gas that comes out of human skin? Nope.

   1%
2. B

   Correct74% picked this

   Mosquitoes are not attracted to humans by

   Why this is right

   When answer choices on Necessary Assumption use "not" to rule out an idea, that's very attractive to us. We should negate it to see whether it weakens. If "mosquitoes are attracted to humans by body heat" would that weaken the argument? Yes! That would be a different explanation for why they like human arms more than just those two gases they like. When we negate this answer, it's letting us say, "in the experiment, the mosquitoes liked the human arm more than the CO2 / lactic acid because they were attracted to the body heat coming off the human arm, not because there was some other gas in addition to CO2 / lactic acid that the mosquitoes liked".

   Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

   74%
3. C

   Irrelevant Comparison2% picked this

   Human skin gives off gaseous substances in greater amounts during the day

   The author wasn't assuming that human skin had any sort of variation in how much gas it gave off in different situations. This conversation is seemingly assuming that human skin is constantly in a state of giving off an array of gases, and the author makes no distinction about different time periods.

   2%
4. D

   Irrelevant Comparison15% picked this

   Mosquitoes are not more successful in finding a bare human arm in darkness

   When answer choices on Necessary Assumption use "not" to rule out an idea, that's very attractive to us. We should negate it to see whether it weakens. If "mosquitoes are more successful finding a bare arm in darkness" would that weaken the argument? Is that a different explanation for why they like human arms more than just those two gases? No. Being better at finding an arm when the lights are out doesn't explain why they want to go to the arm in the first place. If mosquitoes are better at finding arms in the dark, does that disrupt the author's storyline that mosquitoes like at least a third gas that comes out of human skin? Nope. The third gas is coming out of the arm whether it's light/dark, whether it's easier or harder for a mosquito to find a human arm.

   15%
5. E

   Too Strong: never8% picked this

   Human skin never gives off any gaseous substances that

   The author doesn't have to assume that never-ever-ever does human skin ever give off any gaseous substance that repels mosquitoes. Maybe right when we die, our skin expels a nasty death gas that mosquitoes don't like. That wouldn't change the argument in the slightest.

   8%