植物的祖先是进行光合作用的单细胞生物，由此产生的植物可能缺乏真正的根、茎、叶和复杂的生殖结构，如花朵。

The ancestors of plants were photosynthetic single-celled organisms that gave rise to plants presumably lacked true roots, stems, leaves, and complex reproductive structures such as flowers.

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琼·希尔克是洛杉矶加利福尼亚大学的人类学家，他专门从事古代世界猴类的生殖策略的研究。 他说，不过，其他的类人物种也会合作。

After all, other primates cooperate, said anthropologist Joan Silk of the University of California, Los Angeles, who specializes in reproductive strategies of old-world monkeys.

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Steptoe已经使用这种方法从生殖道收集到液体并且他相信也能够使用这个方法来提取卵细胞。 作为平等的合作伙伴，他们成立了自己的道德准则。

Steptoe was already using the method to withdraw fluid from the reproductive tract and agreed that he could also use it to extract eggs.

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