OE


From the context of the sentence, you can tell that choices B and C, "malignant" and "pathogenic," are incorrect. The blank that you need to complete must be the opposite of the word "harmful" and both "malignant" and "pathogenic" are harmful. Choice D is incorrect because "benevolent" means "doing good, showing goodwill" and refers to people and organizations. Choice F, "benign," is incorrect because it means "harmless, having little or no effect, showing mildness." The context requires two words that have a positive effect, choices $\(A\)$ and $\(F\)$, "helpful" and "beneficial."