It can come from animal sources and from vegetable sources, and the two have different impacts on health.

它可能来自动物,也可能来自植物,这两种对健康的影响各不相同

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Imagine two genes, two sorts of animals each containing their own gene.

想象两个基因，两种动物各自含有自己的基因。

耶鲁公开课 - 心理学导论课程节选