单选题 The ultimate constituents of anything that exists are atoms: atoms are real and nothing else is.
A. discovery B. dimensions C. components D. correspondents

【正确答案】 C
【答案解析】[解析] 划线词constituents“成分，要素”。A项discovery“发现”；B项dimensions“尺度”；C项components“成分”；D项correspondents“通讯记者”。C项语意与之符合。