Official Solution:
A fatal disease caused by the parasite Encarsia formosa and spread by greenhouse whiteflies has already killed 50 percent of the cucumber crops planted on the Redfern farm, the largest cucumber producing farm in the northeastern United States. Trialeurodes vaporariorum kills the larvae of greenhouse whiteflies. In an effort to save the remaining cucumber crops on the farm, plant biologists plan to introduce Trialeurodes vaporariorum to the cucumber fields of Redfern farm.
Which of the following, if true about Trialeurodes vaporariorum, provides the strongest evidence that the plan will succeed?
A. It is spread by a type of earthworm that lives on the farm near greenhouse whiteflies' hatching sites.
B. It has been known to lay dormant in cucumber plants for five years or more before it begins to reproduce.
C. It spreads more slowly than
Encarsia formosa under most conditions.
D. It does not destroy some commonly found subspecies of greenhouse whiteflies.
E. It has been known to kill wheat and barley crops by attacking their nutrient intake capabilities.
We want to strengthen the conclusion that a plan to introduce the organism
Trialeurodes vaporariorum to the cucumber fields will succeed. This organism kills the larvae of greenhouse whiteflies, which cause a fatal disease that kills cucumber crops. The plan's goal is to save the cucumber crops. Therefore, evidence that
Trialeurodes vaporariorum will effectively kill the larvae or the prevent the disease from infecting the crops will strengthen the conclusion.
Choice
A supports the conclusion by providing evidence that the larvae of greenhouse whiteflies will be affected by the organism; if a worm spreads
Trialeurodes vaporariorum to the larvae, it is more likely that greenhouse whiteflies will become infected with
Trialeurodes vaporariorum, die, and cease to infect the cucumber plants.
Choice B weakens the argument by stating that the plan will take a long time to enact, and during this lag, the cucumber plants will continue to die.
Choice C states that under most conditions,
Trialeurodes vaporariorum spreads more slowly than
Encarsia formosa does. This does not strengthen the argument, because if anything, it reduces the chance that
Trialeurodes vaporariorum will be effective.
Answer D states that
Trialeurodes vaporariorum does not destroy some common subspecies of greenhouse whiteflies. Subspecies of greenhouse whiteflies are not mentioned and are outside of the scope of the argument; greenhouse whiteflies' subspecies may or may not infect cucumber crops.Furthermore, we want to strengthen the argument by giving evidence that the whiteflies WILL be killed.
Choice E is also outside the scope of the argument; the effect of
Trialeurodes vaporariorum on other crops is irrelevant.
Answer: A