单选题 All living creature are thought to ______ an organism that came into being three billion years ago.
A. descend to B. descend on C. descend into D. descend from

【正确答案】 D
【答案解析】人们认为所有的生物都是在三十亿年前起源于微生物。
[答题点拨] descend to屈尊去做某事。descend on袭击。descend into向下行。descend from起源于。