By competing with rodents for seeds, black ants help control rodent populations that pose a public health risk.
However,
a very aggressive species of blank ant, the Loma ant, which has
recently invaded a certain region, has a venomous sting that is often
fatal to humans.
Therefore, the planned introduction into that region of ant flies, which prey on Loma ants, would benefit public health.
Which of the following, if true, most strengthens the argument?
A.
Ant flies do not attack black ants other than Loma ants. B Loma ants are less effective than many bird species in competing with rodents for seeds. C Certain other species of black ants are more effective than Loma ants in competing with rodents for seeds. D The sting of Loma ants can also be fatal to rodents. E The use of pesticides to control Loma ants could have harmful effects on the environment.
A和C之间徘徊。第一眼看是A,但想想C也对。
A就不说了。说说对C的理解
我认为C说的是这么回事：Loma争抢seeds的效果比不上其他black ants,又由于competing seeds决定了rodent population, 所以Loma在抑制rodent population上发挥的作用不重要。
于是把引入ant flies杀掉Loma，不会影响对于rodent population的控制效果。于是C也strenthen了原文。
我觉得A和C都在strengthen原文。
并且A和C必须同时成立。
请教大家。 | 
