Agricultural Scientist: Vineyards in the Aris Valley that planted crimson clover between vine rows experienced a 40 percent lower incidence of grapevine leafroll virus than vineyards maintaining bare soil. Because crimson clover attracts predatory lady beetles that feed voraciously on mealybugs, which are the sole vectors of leafroll virus, the clover reduces viral infection specifically by suppressing the mealybug population.
Statement: If true, the discovery that vineyards with crimson clover maintained average mealybug densities per vine identical to those in bare-soil vineyards weakens the agricultural scientist's argument.
Cevap: Cevap
Cevap
True, because evidence showing unchanged mealybug populations directly undermines the author's claim that clover reduces viral disease specifically by suppressing mealybug numbers.
The correct assessment is True because the scientist's conclusion specifically attributes the disease reduction to the suppression of mealybug populations. If clover vineyards had the exact same density of mealybugs as bare-soil vineyards, the reduction in disease transmission must be due to some other factor, thereby directly undermining the scientist's explanatory hypothesis.
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Anahtar Kavram
Undermining a causal conclusion by providing evidence that the proposed causal mechanism did not occur.