单选题 Through many years of evolution, your body has learned bow to respond to stress basing on its instinct for survival.

【正确答案】 A
【答案解析】[解析] 根据本句内容，划线部分应填部分是分词作宾语补足语。因此处于宾补与宾语(how to respond to stress)之间是被动关系，所以应填过去分词，选项A为答案。