Studies of both animals and humans have shown that sex hormones somehow affect the stress response, causing females under stress to produce more of the trigger chemicals than do males under the same conditions.
主干
Studies have shown
定语
介词结构作后置定语: of both animals and humans 修饰 studies
介词结构作后置定语:under stress 修饰females;under the same conditions 修饰 males
从句
that宾语从句: that sex hormones…females under stress…males under the same conditions
宾语从句中嵌套比较状语从句: than do males under the same conditions