Self-study
Support Many species of plants produce nectars known as extrafloral nectories (EFNs), which are known to attract certain ants that defend the plants against leaf-eating insects. █████████ ██████████ ███████████ ████ █████ ████ ███████ ███████ ████ ████ ██████ ████ ██████ ████ ███ █████ ████ █████ ████ ████ ████ ████ ██████ ███████ █████ ███ █████████ ███ ███ ███████ ███ ████ ███ █████ ███████ ███████ ██████████ ██████ █████████████ ██████ ███████ ███████████ ████████
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.
10.
Which one of the following, ██ █████ █████ ████ ██████████ ███ ████████ ██████
a
For many species ██ ████████████████ ███████ ████████████ ██ █████████ ████ █ █████ ██ █████████ ████ ███████████ ████████
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, ███ ████████████ ██ ███████ ███████ ████ ██ ███████████ ███ ████████ ██ █ ███████████ ████████ ██ ███ ██████████ ██ █████████████ ███████
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.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
c
Some species of █████████████ ██████ ██████ ███████ ███████ ████ ███████ █████ ██████████ ████ ████ ███████████ ████████
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 ██ ███████ █████ ████ ███████ ███████ ███████ ████ █████ █████ █████ ██ ███████ ██ ███ ██████ █████████████ ███████
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 ███████████ ██ ████ ████ ████ ██ ████ █████ ███████████ ██ █████████████ ███████
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.