WillGetIt wrote:
Between 1980 and 2000 the sea otter population of the Aleutian Islands declined precipitously. There were no signs of disease or malnutrition, so there was probably an increase in the number of otters being eaten by predators. Orcas will eat otters when seals, their normal prey, are unavailable, and the Aleutian Islands seal population declined dramatically in the 1980s. Therefore, orcas were most likely the immediate cause of the otter population decline.
Which of the following, if true, most strengthens the argument‘?
A The population of sea urchins, the main food of sea otters, has increased since the sea otter population declined.
B. Seals do not eat sea otters, nor do they compete with sea otters for food.
C. Most of the surviving sea otters live in a bay that is inaccessible to orcas.
D. The population of orcas in the Aleutian Islands has declined since the 1980s.
E An increase in commercial fishing near the Aleutian Islands in the 1980s caused a slight decline in the population of the fish that seals use for food.
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Responding to a pm:
Again, Official Answers are not debatable and really, I haven't seen an exception, at least in the verbal section.
Try to understand the logic of (C).
They have very smartly used the word: "surviving".
Let's take the argument first.
Premises:
Sea otter population declined - but no sign of disease and malnutrition so predators might have been responsible.
Seal population declined dramatically.
Orcas eat otters when seals are not available.
Conclusion:
Orcas must have led to otter population decline.
We need to strengthen that orcas are responsible for the huge decline in otter population.
C. Most of the surviving sea otters live in a bay that is inaccessible to orcas.
Had the option said, "Most sea otters live in a bay that is inaccessible to orcas," then the option would have weakened our argument.
But the option says, "Most of the
surviving sea otters live in a bay that is inaccessible to orcas." This means that the otters that are left are the ones where orcas cannot reach. Wherever orcas can reach, otters have disappeared from there. It means that it is highly probable that orcas have been binging on otters wherever possible.
Imagine a meadow which was full of grass 2 months back. A small part of the meadow is fenced. Some cattle was introduced in the meadow two months back. What happens if after to months you see that most of the grass is gone except the small part which was fenced? The likely reason is that the cattle ate the grass and hence reduced it.
This is the same concept.
None of the other options are relevant.
A The population of sea urchins, the main food of sea otters, has increased since the sea otter population declined.
Irrelevant
B. Seals do not eat sea otters, nor do they compete with sea otters for food.
What seals eat is none of concern. What we need to strengthen is that orcas ate up the otters.
D. The population of orcas in the Aleutian Islands has declined since the 1980s.
This doesn't strengthen that orcas ate the otters. Perhaps some orcas couldn't adapt to decrease in seal population. We don't know.
E An increase in commercial fishing near the Aleutian Islands in the 1980s caused a slight decline in the population of the fish that seals use for food.
This might affect seal population. It doesn't strengthen that orcas ate otters.
Answer (C)
How is (B), out of scope? Does it not eliminate other cause and effect to the argument?
close
16 Nov 2020, 10:23
