Summarize Argument
The author argues that drunk drivers are deterred by the prospect of severe penalties. This is because statistics show that countries with the most severe penalties for drunk driving have a smaller percentage of alcohol-related traffic accidents when compared to other countries.
Notable Assumptions
The author assumes that there are no other factors, such as cultural differences, in the countries with harsh punishments for drunk driving that would explain the lower rates of drunk driving accidents.
A
The countries with the largest populations do not have severe penalties for driving while intoxicated.
This is irrelevant to the reasoning of the argument. The size of countries with/without severe penalties does not impact the causal relationship between severe penalties and the rates of drunk driving accidents.
B
Very severe penalties against driving while intoxicated are in effect only in countries in which alcohol use is rare.
This weakens the argument by calling out one of the author’s main assumptions. If alcohol use is already rare in countries with the strictest penalties, then the low rate of alcohol-related driving accidents might be due to low alcohol consumption.
C
The higher a country’s speed limits, the more frequent traffic accidents tend to be in that country.
A country’s speed limits are irrelevant to the relationship between strict penalties and the rate of drunk driving accidents. You need to make a lot of unwarranted assumptions for this answer choice to work.
D
Only a relatively small minority of those who drive while intoxicated are actually apprehended while doing so.
Whether or not drunk drivers are apprehended is irrelevant to the relationship between strict penalties and the rate of drunk driving accidents. Also, this does not address the comparison between countries with/without strict penalties.
E
All countries impose severer penalties on those who cause accidents while driving intoxicated than on those who are merely apprehended while driving intoxicated.
This is irrelevant to the argument because it does not address how the severity of penalties impacts the rate of drunk driving accidents. This fact does not change anything about the argument.
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that jumping spiders defend EFN-producing plants against leaf-eating insects. He supports this by noting that ants that display behavior similar to that of the spiders defend the plants. He then cites experiments showing that the spiders land on plants with active EFNs six times more often than on those without EFNs, and they regularly eat the plant's nectar.
Notable Assumptions
The author assumes that there’s no alternative explanation for the spiders’ attraction to the EFN-producing plants, simply because the spiders’ behavior is similar to the ants’ behavior. He implicitly rules out all other explanations. But maybe the spiders just land on the plants for food and have a neutral or even negative effect on the plants’ health.
A
For many species of nectar-producing plants, productivity is increased when a plant is protected from leaf-eating insects.
Irrelevant—this doesn’t rule out any alternative explanations for the spiders’ behavior. It makes sense that plants are more productive when protected from leaf-eating insects, but (A) doesn’t address whether the spiders themselves are actually protecting the plants.
B
In field experiments, the introduction of jumping spiders into an environment was followed by a significant increase in the population of EFN-producing plants.
This strengthens the author’s hypothesis by validating a prediction that would follow from it. If his hypothesis were true, we’d expect to see the plants thriving and reproducing when the spiders are introduced, since the spiders protect them from leaf-eating insects.
C
Some species of EFN-producing plants cannot survive without some outside agent protecting them from leaf-eating insects.
Irrelevant— this fails to address whether jumping spiders are protecting the plants from leaf-eating insects and thus fails to strengthen the argument.
D
Experiments with types of spiders other than jumping spiders suggest that these other types of spiders do not defend EFN-producing plants.
Irrelevant— the argument is only concerned with whether or not the jumping spiders defend EFN-producing plants. The effect of other types of spiders on EFN-producing plants doesn’t matter.
E
Regions with large populations of ants also tend to have large populations of EFN-producing plants.
Irrelevant— we already know that certain ants protect EFN-producing plants from leaf-eating insects, so it makes sense that areas with lots of ants also have lots of EFN-producing plants. But (E) fails to address whether jumping spiders also protect these plants.