Ecologist: Without the intervention of conservationists, squirrel monkeys will become extinct. But they will survive if large tracts of second-growth forest habitat are preserved for them. Squirrel monkeys flourish in second-growth forest because of the plentiful supply of their favorite insects and fruit.
Summary
First sentence - “Without” is used just like “unless” here, so it means:
If there is NO intervention of conservationists → squirrel monkeys extinct
Second sentence - “If” introduces the sufficient condition:
Tracts of second-growth forest preserved → squirrel monkeys NOT extinct
The last sentence tells us why squirrel monkeys “flourish” in second-growth forest. But it is not a conditional and does not connect to the conditionals in the first two sentences.
Very Strongly Supported Conclusions
We can connect the first two sentences, although you need to do the contrapositive of one or the other to see the connection:
If there is NO intervention of conservationists → squirrel monkeys extinct → tracts of second-growth forest NOT preserved
OR
If tracts of second-growth forest preserved → squirrel monkeys NOT extinct → there was intervention of conservationists
A
No habitat other than second-growth forest contains plentiful supplies of squirrel monkeys’ favorite insects and fruit.
Not supported. We know that second growth forests have a lot of the favorite insects and fruit. This doesn’t imply that other habitats don’t have these things.
B
At least some of the conservationists who intervene to help the squirrel monkeys survive will do so by preserving second-growth forest habitat for the monkeys.
If the monkeys survive, we know that second-growth forests have been preserved. And we know that this implies the conservationists intervened. But we don’t know exactly *how* the conservationists intervened. What they did might be unrelated to the forests. The forests were preserved, sure; but we don’t know that the conservationists helped to preserve the forests.
C
Without plentiful supplies of their favorite insects and fruit, squirrel monkeys will become extinct.
We know that without the intervention of conservationists, the monkeys will go extinct. But we have no idea whether lack of favorite fruits and insects will lead to extinction. The monkeys can “flourish” because of those fruits and insects; but this doesn’t imply that without those things, the monkeys will die.
D
If conservationists intervene to help squirrel monkeys survive, then the squirrel monkeys will not become extinct.
This confuses sufficient and necessary conditions. We know that if conservationists DON’T intervene, the monkeys will go extinct. This does not imply that if conservationists DO intervene, that the monkeys will survive.
E
Without the intervention of conservationists, large tracts of second-growth forest habitat will not be preserved for squirrel monkeys.
(E) is supported by the connection between the first two sentences:
If there is NO intervention of conservationists → squirrel monkeys extinct → tracts of second-growth forest NOT preserved
A
Several colleagues of the professor have found that, in their non-business courses, several of their students behave similarly in relation to assignments placed on the computer network.
B
Studies consistently show that most computer users will print reading material that is more than a few pages in length rather than read it on the computer screen.
C
Some people get impaired vision from long periods of reading printed matter on computer screens, even if they use high quality computer screens.
D
Scanning technology is very poor, causing books delivered via computer to be full of errors unless editors carefully read the scanned versions.
E
Books on cassette tape have only a small fraction of the sales of printed versions of the same books, though sales of videos of books that have been turned into movies remain strong.
Politician: The current crisis in mathematics education must be overcome if we are to remain competitive in the global economy. Alleviating this crisis requires the employment of successful teaching methods. No method of teaching a subject can succeed that does not get students to spend a significant amount of time outside of class studying that subject.
Summary
The stimulus can be diagrammed as follows:
Notable Valid Inferences
If we are to remain competitive in the global economy, we must get students to study math outside of class.
If we are to overcome the crisis in math education, we must get students to study math outside of class.
If students don’t spend a significant amount of time studying math outside of class, then we won’t remain competitive in the global economy.
A
If students spend a significant amount of time outside of class studying mathematics, the current crisis in mathematics education will be overcome.
This could be false. Spending a significant time outside of class studying math is a necessary condition, not a sufficient condition, of resolving the crisis.
B
The current crisis in mathematics education will not be overcome unless students spend a significant amount of time outside of class studying mathematics.
This must be true. As shown in the diagram, by chaining conditional claims, we see that studying math outside of class is a necessary condition of overcoming the crisis
C
Few subjects are as important as mathematics to the effort to remain competitive in the global economy.
This could be false. The stimulus does not talk about the relative importance of other subjects.
D
Only if we succeed in remaining competitive in the global economy will students spend a significant amount of time outside of class studying mathematics.
This could be false. Remaining competitive in the global economy is a sufficient condition, not a necessary condition, of spending a lot of time studying math outside of class.
E
Students’ spending a significant amount of time outside of class studying mathematics would help us to remain competitive in the global economy.
This could be false. We know that spending lots of time outside of class studying math is a necessary condition of remaining competitive. However, that’s not logically the same as “helping.”
The question stem reads: The reasoning in which of the following is most similar to that in the naturalist's argument? This is a Parallel question.
The naturalist begins by claiming that a species can survive the change in an environment as long as the change is not too rapid. The naturalist has provided a general rule saying that the change can be ok for a species, with the caveat that the change does not occur too rapidly. The naturalist concludes that the threats humans create to woodland species arise not from cutting down trees but from the rate at which we are cutting down trees. The naturalist has applied the universal rule about species to the specific example of woodland species. So the problem is not that change we are creating by cutting down trees, but the because we are causing the change too rapidly.
When evaluating an answer choice, we need a universal rule with a caveat. The correct AC will apply that universal rule to a specific example and say that the specific example is failing to satisfy the caveat.
Answer Choice (A) is incorrect. (A) does not provide a universal rule; it only gives a specific rule about fossil fuels. Additionally, (A) 's rule about fossil fuels lacks the caveat we are looking for.
Answer Choice (B) is incorrect. We can quickly eliminate (B) because of the word "many." Remember, we need a universal rule, so if (B) was right, it would begin with "all people." Additionally, (B) 's rule lacks the caveat we are looking for, nor does (B) apply its rule to a specific example.
Answer Choice (C) is incorrect. Similar to (B), we can eliminate (C) because it says "some" when we are looking for a universal rule. Additionally, (C) also lacks the caveat, nor does (C) apply the rule to a specific example.
Correct Answer Choice (D) matches the stimulus. (D) provides a general rule that "people do not fear change," under the caveat people know what the change will bring. (D) then applies that rule to the specific example of the author's company's employees. The company's employees' fears arise from the fact the company is changing, but because they do not know what the change will bring (the caveat is not satisfied).
Answer Choice (E) is incorrect. (E) does not provide a general rule, so we can eliminate it.