Differences among believers are common; however, it was the pressure of religious persecution that exacerbated their conflicts and created the split of the union.
【正确答案】 B
【答案解析】解析：划线词exacerbate的含义是“使加剧，恶化”。选项A为“根除”，选项C为“征服，击败”，选项D为“避免、防止”。