Self-study
Two lakes in the Pawpaw mountains, Quapaw and Highwater, were suffering from serious declines in their fish populations ten years ago. █████ ████ █████ █████ ███ ████ █ ██████████ ██ ███████ ██ ██████ █████ ███ ███ ████ ██████████ █████ ███ ██████████ ██ █████████ █████ ██ ████ ██████████ ███ ████ ████████ ███ ███ ████ ██████████ ███ █████████ ██ ████████ █████ ███ ███ ██ ███████ ██ ████████ ███████████ ███ ███ ███████ ██ ███ ████ ██████████ ██ ██████ █████
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that a ban on fishing caused the fish population at Quapaw Lake to rebound, after declining ten years ago. The evidence is that the fish population at Quapaw Lake rebounded after a fishing ban was put in place. On the other hand, the fish population at Highwater Lake, where there was a similar decline but no fishing ban, didn’t rebound.
Based on observing a difference in outcome between the two lakes, the author hypothesizes that the fishing ban played a causal role. To undermine this argument, we can offer an alternative explanation, likely in the form of another relevant difference between the lakes. We can also look for evidence to the contrary, for example that fishing bans are poorly enforced and rarely decrease fishing.
9.
Which one of the following, ██ █████ ████ █████████ ███████ ███ ████████ ██████
a
Highwater Lake is ██ ██ ████ ██ ███ █████████ ████ ██ ██████ ███████████ ██ ████ █████
This could be an alternative explanation if it told us that Quapaw Lake was different in this regard. However for all we know, Quapaw Lake has the same problem, so this doesn't weaken.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
b
Prior to the ████ █████ ███ ███████████ ██ ███████ ██ ██████ █████
This gives us contrary evidence: if there was minimal fishing in Quapaw Lake to begin with, then the ban couldn't have a significant impact. This weakens by undermining the cause-and-effect connection.
Alternate explanation
Alternate explanation
Weaken: Introduce or support an alternate explanation for a phenomenon.
Strengthen: Helps to eliminate an alternate explanation for a phenomenon.
c
Highwater Lake is ████ ██████ ████ ██████ █████
If we knew anything about how the size of a lake impacts its fish population, this could be useful. But because we don't know anything of the sort, this is irrelevant to the argument.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
d
Several other lakes ██ ███ ██████ █████████ ████ ████████ ███ █████████ ██ █████ ████ ████████████
It's impossible to know whether the population increases at those other lakes were the result of fishing bans or other, alternative causes. Because we don't have enough information, this doesn't affect the argument.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
e
There used to ██ █ ███████ ███████ ██ ████ ███████ ██ █████████ ████ ████ ██ ██████ █████ ███ █████ ██ ██████ ███
Like with (C), this might be useful if we had more information about what factors affect a fish population (for example if species diversity helps with population recovery), but since we don't, this isn't relevant.