A new agricultural technique promises to significantly increase crop yields by using genetically modified (GM) seeds that are resistant to a specific herbicide. Farmers adopting this technique are advised to apply the herbicide liberally to control weeds, which would otherwise compete with the GM crops. Environmental activists argue that this technique will inevitably lead to a decrease in biodiversity due to the widespread use of a potent herbicide. Which of the following, if true, would most seriously weaken the activists' argument?
- AThe herbicide used with the GM seeds is highly selective, affecting only the target weeds and breaking down rapidly in the soil.
- BFarmers who adopt the GM seeds typically have larger farms and already use various other pesticides.
- CThe increased crop yields from the GM seeds could reduce the amount of land needed for agriculture, preserving natural habitats.
- DSome weeds have already begun to develop resistance to the specific herbicide used with the GM seeds.
Show answer & explanationAnswer & explanation
Correct answer: A. The herbicide used with the GM seeds is highly selective, affecting only the target weeds and breaking down rapidly in the soil.
The activists' argument hinges on the idea that 'widespread use of a potent herbicide' will 'inevitably lead to a decrease in biodiversity.' If the herbicide is highly selective and breaks down rapidly, its impact on non-target species and the broader environment (and thus biodiversity) would be minimal, directly weakening the inevitability of decreased biodiversity.
Why the other options are wrong
- B. This describes existing practices of some farmers but doesn't address the specific impact of *this new technique's* herbicide on biodiversity.
- C. This suggests an *indirect* benefit to natural habitats (and thus biodiversity) by reducing land use, but it doesn't directly weaken the claim about the *herbicide's impact* on biodiversity where it is applied.
- D. Weed resistance suggests the *effectiveness* of the herbicide might decline, but it doesn't weaken the claim that its widespread use *would* decrease biodiversity if it were effective against a wide range of plants.
Challenging Inevitable Outcomes
To challenge a claim of an 'inevitable' negative outcome, provide evidence that mitigates the risk, demonstrates alternative possibilities, or shows the underlying premise is flawed.
- Examine the mechanism of harm.
- Look for mitigating factors.
- Question the scope of the impact.
Memory trick: When a future is 'certain', check the 'how' and 'what if', or the curtain won't close on the predicted rift!