QUESTION TEXT: One of the advantages of Bacillus thuringiensis…
QUESTION TYPE: Weaken
CONCLUSION: The BT bacterial toxins are better than chemical pesticides for pest control.
REASONING: The toxins only harm the insects in question. They don’t harm birds or the insects that prey upon the pest insects.
ANALYSIS: The correct answer shows how BT toxins have a disadvantage against chemical toxins. The wrong answers mostly show limitations of BT toxins. These don’t help, because they are limitations that likely also affect chemical pesticides.
- This could be bad, if the chemical insecticides kill beneficial insects.
- That’s fine. The stimulus argues that the toxins should be used in combination. It always says BT toxins, plural.
- This doesn’t matter. We have no evidence that chemical insecticides would harm weeds.
- CORRECT. The BT toxins could work better at first but then slowly become ineffective.
- So? The stimulus didn’t claim that BT toxins will fix every problem.
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