Researchers have saved some of Sudan's DNA and they're hoping to use it to keep the sub species alive.

研究人员已经保存了一些苏丹的DNA，他们希望用它来保持亚种的存活。

Nevertheless, no certain criterion can possibly be given by which variable forms, local forms, sub species and representative species can be recognised.

然而， 不可能给出识别变异型、地方型、 亚种和代表种的特定标准。

And the sub species of the white rhino known as the northern white rhino is now just two animals away from complete extinction and both of the living ones are females.

白犀牛的亚种被称为“北白犀牛”，现在只剩下两只，它们濒临灭绝，活着的两只犀牛都是雌性。