Critical Reasoning

Nutritionists are advising people to eat more fish, since the omega-3 fatty acids in fish help combat many diseases If everyone took this advice, however, there would not be enough fish in oceans, rivers, and lakes to supply the demand; the oceans are already being overfished. The obvious method to ease the pressure on wild fish populations is for people to increase their consumption of farmed fish.

Which of the following, if true, raises the most serious doubt concerning the prospects for success of the solution proposed above?

a) Aquaculture, or fish farming, raises more fish in a given volume of water than are generally present in the wild.
b) Some fish farming, particularly of shrimp and other shellfish, takes places in enclosures in the ocean.
c) There are large expanses of ocean waters that do not contain enough nutrients to support substantial fish populations.
d) The feed for farmed ocean fish is largely made from small wild-caught fish, including the young of many popular food species.
e) Some of the species that are now farmed extensively were not commonly eaten when they were only available in the wild.

OA:D

NandishSS wrote:Nutritionists are advising people to eat more fish, since the omega-3 fatty acids in fish help combat many diseases If everyone took this advice, however, there would not be enough fish in oceans, rivers, and lakes to supply the demand; the oceans are already being overfished. The obvious method to ease the pressure on wild fish populations is for people to increase their consumption of farmed fish.

Which of the following, if true, raises the most serious doubt concerning the prospects for success of the solution proposed above?

a) Aquaculture, or fish farming, raises more fish in a given volume of water than are generally present in the wild.
b) Some fish farming, particularly of shrimp and other shellfish, takes places in enclosures in the ocean.
c) There are large expanses of ocean waters that do not contain enough nutrients to support substantial fish populations.
d) The feed for farmed ocean fish is largely made from small wild-caught fish, including the young of many popular food species.
e) Some of the species that are now farmed extensively were not commonly eaten when they were only available in the wild.

OA:D

Conclusion: to ease pressure on the wild fish population, people should eat more farmed fish.

If we want to weaken this conclusion, we're looking for an answer choice that shows eating more farmed fish would not be beneficial for the wild fish population. (Or may even be harmful.)

D shows that farmed fish require wild fish as food. Thus, when people eat more farmed fish, more wild fish will be required to feed the farmed fish, depleting the very wild fish populations the plan was intended to spare. Looks like a pretty good weakener. We've got our answer.