Summarize Argument: Phenomenon-Hypothesis
The zookeeper hypothesizes that Jocko’s silence was meant to keep the other chimpanzees from taking his food. She supports this by showing that Jocko only remained silent after an earlier incident, where his bunch of bananas were taken away by other chimpanzees after he barked excitedly.
Notable Assumptions
The zookeeper assumes that the difference between Jocko’s reactions weren’t a result of getting a different quantity of food: the first day he gets a bunch of bananas, whereas the second he gets only one. This means the zookeeper doesn’t believe that Jocko was actively trying to share his food the first time, or that the quantity of food itself didn’t cause him to bark out of excitement.
A
Chimpanzees utter food barks only when their favorite foods are available.
Jocko received bananas both times. He didn’t bark the second time.
B
Chimpanzees utter food barks only when they encounter a sizable quantity of food.
Jocko wasn’t trying to keep the others from taking his food the second time. He simply hadn’t received a sufficient quantity of food to utter a food bark.
C
Chimpanzees frequently take food from other chimpanzees merely to assert dominance.
Perhaps that’s what happened the first time, but we don’t care. We’re looking for something to weaken the claim that Jocko didn’t bark the second time to keep other chimpanzees from taking his food.
D
Even when they are alone, chimpanzees often make noises that appear to be signals to other chimpanzees.
Jocko didn’t make any noise the second time. We need to know why.
E
Bananas are a food for which all of the chimpanzees at the zoo show a decided preference.
We need to weaken the zookeeper’s claim that Jocko kept quiet to protect his food. This just tells us all chimps like bananas.
Summarize Argument
We are asked to supply an additional premise to fill in the blank.
The author concludes that gardeners can boost potato yields by planting stinging nettles nearby. He explains that nettles attract insects that kill harmful pests. Although nettles also attract aphids, many of which can harm potatoes, the author says this doesn't contradict his recommendation because _______.
Notable Assumptions
The author assumes that the nettles don’t harm the potato plants. He also assumes that, just because the nettles attract insects that kill pests, this will directly boost potato yields.
To effectively fill in the blank, the correct answer must somehow show that the aphids that are attracted to stinging nettles either don’t harm potato plants or else don’t harm them enough to affect their potato production.
To effectively fill in the blank, the correct answer must somehow show that the aphids that are attracted to stinging nettles either don’t harm potato plants or else don’t harm them enough to affect their potato production.
A
stinging nettles require little care and thus are easy to cultivate
Irrelevant— this fails to show that the aphids that are attracted to nettles do not harm potato yields. Also, whether nettles are easy or difficult to cultivate doesn’t impact the argument that planting them can increase potato yields.
B
some types of aphids are attracted to stinging nettle plants but do not damage them
Irrelevant— this addresses whether some of the aphids damage the nettles, but it fails to address whether the aphids damage the potato plants.
C
the types of aphids that stinging nettles attract do not damage potato plants
If the aphids that are attracted to the nettles do not damage potato plants, then the aphids don’t contradict the author’s recommendation to plant nettles nearby in order to boost potato yields.
D
insect pests typically cause less damage to potato plants than other harmful organisms do
Even if insect pests cause less damage than other organisms, they might still cause a lot of damage. (D) fails to address whether the aphids that are attracted to the nettles damage potato plants enough to reduce their potato yield.
E
most aphid species that are harmful to potato plants cause greater harm to other edible food plants
Irrelevant— it doesn't matter how much harm aphids cause to other plants. The argument is only about increasing the yield of potato plants, and (E) fails to show whether the aphids harm potato plants enough to reduce their yield.
Summarize Argument
The argument concludes that trends in publishing are not based on the true interests of the public. This is based on the claim that journalism students are more interested in different stories than the ones that are most commonly published.
Identify and Describe Flaw
This is a cookie-cutter unrepresentative sampling flaw. Journalism students’ tastes in stories are not likely to represent the general public’s interests: they will probably be more interested in serious political and governmental issues, even if the public is truly interested in trends and gossip. So, this survey does not really support the conclusion that publishing is based on false assumptions about public interests.
A
It takes what is more likely to be the effect of a phenomenon to be its cause.
The argument never discusses or relies on the idea of cause and effect relationships.
B
It regards the production of an effect as incontrovertible evidence of an intention to produce that effect.
The argument doesn’t involve any questions of whether an effect was caused intentionally or not.
C
It relies on the opinions of a group unlikely to be representative of the group at issue in the conclusion.
The argument uses the opinions of journalism students to draw a conclusion about the general public’s journalism preferences. This is likely to be an unrepresentative sample.
D
It employs language that unfairly represents those who are likely to reject the argument’s conclusion.
The argument never refers in any way, fairly or unfairly, to those who are likely to reject the argument’s conclusion.
E
It treats a hypothesis as fact even though it is admittedly unsupported.
The argument doesn’t treat an unsupported hypothesis as a fact. In fact, there isn’t any stated hypothesis which the argument admits is unsupported to begin with.
"Surprising" Phenomenon
Why do experts recommend other pest-control methods when bug zappers are very effective?
Objective
A hypothesis resolving this discrepancy will give a reason for pest control experts to prefer birds and insecticides over bug zappers. It will give a reason to avoid bug zappers despite their general effectiveness, or imply that insect-eating birds and insecticides are even more effective.
A
Insect-eating birds will take up residence in any insect-rich area if they are provided with nesting boxes, food, and water.
This does not explain why experts recommend insect-eating birds over bug zappers. It explains why the birds are effective pest-control measures, but makes no comparison with bug zappers.
B
Bug zappers are less effective against mosquitoes, which are among the more harmful insects, than they are against other harmful insects.
This does not provide a reason to favor insect-eating birds and insecticides because it takes no position on the effectiveness of those measures against mosquitos. It is possible birds and insecticides are equally or even less effective against mosquitos.
C
Bug zappers use more electricity but provide less light than do most standard outdoor light sources.
This does not explain why experts would avoid recommending bug zappers as a form of pest control. There is no evidence that pest control experts make their recommendations based on the solutions’ efficiency at turning electricity into light.
D
Bug zappers kill many more beneficial insects and fewer harmful insects than do insect-eating birds and insecticide sprays.
This explains why experts recommend birds and insecticides over bug zappers. Though effective in general, bug zappers are less effective than birds and insecticides at targeting and eliminating insects that are pests.
E
Developers of certain new insecticide sprays claim that their products contain no chemicals that are harmful to humans, birds, or pets.
This does not explain why insecticides or birds are favored by pest-control experts over bug zappers. It does not state that insecticides are any safer than bug zappers.