The economy around Lake Paqua depends on fishing of the lake's landlocked salmon population. In recent years, scarcity of food for salmon there has caused a decline in both the number and the size of the adult salmon in the lake. As a result, the region's revenues from salmon fishing have declined significantly. To remedy this situation, officials plan to introduce shrimp, which can serve as a food source for adult salmon, into Lake Paqua.
In many Plan Critical Reasoning questions, such as this one, the conclusion of the argument is not directly stated. At the same time, the conclusion in a Plan question is basically that the plan will work. So, in this case the implied conclusion is that introducing shrimp into Lake Paqua will remedy the situation involving the decline in number and size of the salmon in the lake.
The support for the conclusion that the plan will work is that shrimp "can serve as a food for adult salmon."
Which of the following, if true, most seriously calls into question the plan's chances for success?
This is a Weaken question, and the correct answer will indicate that, even though shrimp can serve as a food for adult salmon, introducing shrimp into Lake Paqua may not remedy the situation.
A. Salmon is not a popular food among residents of the Lake Paqua region.
This choice has no effect on the argument.
After all, the purpose of the plan is to remedy the situation involving the decline in number and size of the salmon, and the plan can achieve that purpose regardless of whether salmon is a popular food.
Eliminate.
B. Tourists coming to fish for sport generate more income for residents of the Lake Paqua region than does commercial fishing.
This choice has no effect on the argument.
After all this choice presents a comparison of fishing for sport and commercial fishing that is irrelevant in determining whether the plan will work.
Regardless of which type of fishing generates more income, providing food for the salmon could serve to remedy the situation.
Eliminate.
C. The shrimp to be introduced into Lake Paqua are of a variety that is too small to be harvested for human consumption.
The purpose of the plan is not to produce food for human consumption; it's to remedy the situation involving the salmon.
So, this choice doesn't weaken the argument because, even if the shrimp are too small to be harvested for human consumption, the plan could still work. After all, the passage states as fact that the shrimp can serve as food for salmon.
Eliminate.
D. The primary food for both shrimp and juvenile salmon is plankton, which is not abundant in Lake Paqua.
This choice is interesting.
After all, the support for the conclusion that the plan will work is that the shrimp "can serve as a food for adult salmon."
But what about juvenile salmon? They need to eat too in order for the salmon population to recover.
So, if the primary food for both shrimp and juvenile salmon is plankton, which is not abundant in Lake Paqua, then the plan may not work. After all, if the shrimp eat what the juvenile salmon eat, and it's not abundant in Lake Paqua, then the juvenile salmon may not have much to eat.
In that case, the plan may not work.
So, this choice serves to call into question the plan's chances of success.
Keep.
E. Fishing regulations prohibit people from keeping any salmon they have caught in Lake Paqua that are smaller than a certain minimum size.
We need a choice that calls into question the plan's chances of success, but if anything, this choice does the opposite.
After all, if regulations prevent people from keeping salmon they have caught in Lake Paqua that are smaller than a certain size, then we have another reason to believe that the salmon population will recover if there's food for the salmon to eat.
So, if anything, this choice strengthens, rather than weakens, the case for the conclusion that the plan will work.
Eliminate.
Correct answer: D
In many Plan Critical Reasoning questions, such as this one, the conclusion of the argument is not directly stated. At the same time, the conclusion in a Plan question is basically that the plan will work. So, in this case the implied conclusion is that introducing shrimp into Lake Paqua will remedy the situation involving the decline in number and size of the salmon in the lake.
The support for the conclusion that the plan will work is that shrimp "can serve as a food for adult salmon."
Which of the following, if true, most seriously calls into question the plan's chances for success?
This is a Weaken question, and the correct answer will indicate that, even though shrimp can serve as a food for adult salmon, introducing shrimp into Lake Paqua may not remedy the situation.
A. Salmon is not a popular food among residents of the Lake Paqua region.
This choice has no effect on the argument.
After all, the purpose of the plan is to remedy the situation involving the decline in number and size of the salmon, and the plan can achieve that purpose regardless of whether salmon is a popular food.
Eliminate.
B. Tourists coming to fish for sport generate more income for residents of the Lake Paqua region than does commercial fishing.
This choice has no effect on the argument.
After all this choice presents a comparison of fishing for sport and commercial fishing that is irrelevant in determining whether the plan will work.
Regardless of which type of fishing generates more income, providing food for the salmon could serve to remedy the situation.
Eliminate.
C. The shrimp to be introduced into Lake Paqua are of a variety that is too small to be harvested for human consumption.
The purpose of the plan is not to produce food for human consumption; it's to remedy the situation involving the salmon.
So, this choice doesn't weaken the argument because, even if the shrimp are too small to be harvested for human consumption, the plan could still work. After all, the passage states as fact that the shrimp can serve as food for salmon.
Eliminate.
D. The primary food for both shrimp and juvenile salmon is plankton, which is not abundant in Lake Paqua.
This choice is interesting.
After all, the support for the conclusion that the plan will work is that the shrimp "can serve as a food for adult salmon."
But what about juvenile salmon? They need to eat too in order for the salmon population to recover.
So, if the primary food for both shrimp and juvenile salmon is plankton, which is not abundant in Lake Paqua, then the plan may not work. After all, if the shrimp eat what the juvenile salmon eat, and it's not abundant in Lake Paqua, then the juvenile salmon may not have much to eat.
In that case, the plan may not work.
So, this choice serves to call into question the plan's chances of success.
Keep.
E. Fishing regulations prohibit people from keeping any salmon they have caught in Lake Paqua that are smaller than a certain minimum size.
We need a choice that calls into question the plan's chances of success, but if anything, this choice does the opposite.
After all, if regulations prevent people from keeping salmon they have caught in Lake Paqua that are smaller than a certain size, then we have another reason to believe that the salmon population will recover if there's food for the salmon to eat.
So, if anything, this choice strengthens, rather than weakens, the case for the conclusion that the plan will work.
Eliminate.
Correct answer: D