作者：英吉
Paleontologist Stephen Jay Gould has argued that many biological traits are not the products of natural selection, favored due to their enhancement of reproduction or survival, but that they are simply random by-products of other evolutionary developments.
(A) due to their enhancement of reproduction or survival, but that they are
(B) due to the reproduction or survival they enhance, but they are
(C) because they enhance reproduction or survival, but
(D) because they enhance reproduction or survival, but are
(E) because of enhancing reproduction or survival, but are
原文意思：说很多生物特点不是自然选择的产物而是一个什么东西的副产品。
题目分析：原文体现出了一个“不是。。。而是。。。”的并列关系，所以but后面没有必要加they了，因为不是和而是后面的动词发起者没有变化，加they就类似与“英吉不仅杀人而且他放火了”。C和D一个加了are一个没有，前面是are not ，显然是后面加了are会好一些。E当我读到of enhancing的时候，这个动词的发起者就没说出来，需要我自己往上添，感觉不好，干掉！
