Logical Reasoning

PT121 · S4 · Q12 Some species are called “indicator species”

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Some species are called “indicator species” because the loss of a population of such a species serves as an early warning of problems arising from pollution.

Main Conclusion

Environmentalists would be misguided if they attributed the loss of a population to pollution in all cases — i.e., the loss of a specific population should not always be interpreted as a sign of environmental degradation.

Premises

Population declines often signal environmental degradation, but they are just as often the result of an ecosystem's natural evolution. Change is the status quo in nature.

Goal

Find an answer that says: do not always read population loss as environmental degradation.

12.

Which one of the following most accurately expresses the argument's conclusion?

  1. Environmentalists sometimes overreact to the

    Bad Description

    The argument is not about overreaction — it is about misinterpretation. The author warns environmentalists not to attribute every population loss to pollution, not that they overreact when they do. The conclusion is about the interpretive mistake, not the emotional intensity of the response.

    2% picked this

  2. Correct

    The loss of a specific

    Why this is right

    This is the main conclusion. The author's point is exactly that population loss should not always be read as environmental degradation — sometimes it is natural ecosystem evolution. The premises (sometimes natural, change is the status quo) all build to this very claim. The hedge "should not always" matches the argument's precise stance: not "never," just "not always."

    Skill tested: Main Conclusion · how this choice captures the argument's function is the move to repeat next time.

    84% picked this

  3. Environmentalists’ use of indicator species

    Bad Description

    The argument does not say that using indicator species is "often problematic." It says environmentalists would be misguided to attribute population losses to pollution in all cases — that is a narrower point. The use of indicator species can still be valuable; the warning is about how to interpret the signals, not whether the practice itself is problematic.

    7% picked this

  4. The loss of a specific

    Premise

    The first half ("loss is often the result of natural changes") is one of the premises supporting the conclusion. The second half ("should not be resisted") goes beyond the argument — the author never recommends not resisting population losses. The argument is about interpretation, not about whether to act. So this is a premise plus an unsupported addition.

    3% picked this

  5. The loss of a specific

    Bad Description

    The argument says natural change, not pollution-caused population loss, is part of nature's status quo. This answer flips the relationship — claiming pollution-caused population losses are part of nature's status quo. The author never says that, and it is the opposite of the warning being issued.

    3% picked this

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