Self-study
The number of codfish in the North Atlantic has declined substantially as the population of harp seals has increased from two million to more than three million. ████ █████ ███ ████ ███ ███ █████████ ███ ███████████ ███ ███ █████ █ ██████████ ████ ██ ███ ██████ █████ ██ ██ █████████ ████████ ████ ███ ████████ ██ ███ ████ ██████████ ███ ███████████ █████████████ ██ ███ ███████ ██ ███ ███ ███████████
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that an increase in the North Atlantic harp seal population is unlikely to be responsible for a drop in the cod population over the same time period. The author supports this hypothesis by stating that cod is not a significant part of the seals’ diet. After all, if the seals aren’t eating the cod, how could they be responsible for the observed phenomenon of the cod’s decline?
Notable Assumptions
The author assumes that the only possible way that the seal increase could causally contribute to the cod decrease is that the seals directly eat the cod. This overlooks the possibility that the two phenomena have an indirect causal relationship: for example, the seals might eat a different fish that the cod also rely on, or otherwise impact the ecosystem in a way that harms the cod.
5.
Which one of the following, ██ █████ ████ █████████ ███████ ███ █████████
a
People who fish ███ ███ ████████████ ███ ██████████████ ██ ███ ████████ ██ █████ ███████ ██ █████ ████ ███████████ ███████ ████████
This does not weaken the argument. If the seals are actually helping to protect the cod by deterring fishers, that does nothing to undermine the author’s hypothesis that the seals aren’t harming the cod population.
b
Water pollution poses █ ████ ███████ ██████ ██ ███ ████ ██ ███ ████ █████
This does not weaken the argument. In fact, by providing an alternative hypothesis explaining why the cod population might decline that’s unrelated to the seal population increase, this claim would actually strengthen.
c
The harp seal ███████ ██ █████ ████ ██ ███ ████ ██ ███████ █ █████ ██████████ ██ ████
This does not weaken the argument. If anything, this claim would strengthen: it implies that the seals and the cod live in different parts of the North Atlantic, which makes it less likely that the seals would have an impact on the cod population.
d
Cod feed almost ███████████ ██ ████████ █ ████ ████ ██ █ ██████ ██ ███ ████ ██████ █████
This weakens the argument, because it provides an indirect causal mechanism linking the increase in seals and the decline in cod. This rebuts the assumption that the seals must either eat the cod or else not affect them at all, thus undermining the author’s hypothesis.
Alternate explanation
Alternate explanation
Weaken: Introduce or support an alternate explanation for a phenomenon.
Strengthen: Helps to eliminate an alternate explanation for a phenomenon.
e
The cod population ██ ███ █████ ████████ █████ ██ ███████ ██████ ███ █████████ ██████████ █████ ██ █████████
This does not weaken the argument. This claim still doesn’t indicate whatsoever that the seal increase might contribute to the cod decrease. If anything, it strengthens the argument by indicating that the cod decline began independently of the seal increase.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).