这道prep题的标准答案是什么？

gmatgmat

4. Although the turtle has been toothless for more than 150 million years, in some contemporary turtle species the moderately sharp and jagged edges of their horny jaws function for teeth.

A. their horny jaws function for teeth

B. its horny jaws function for teeth

C. its horny jaws function as do teeth

D the horny jaws function as teeth do

E the horny jaws function as teeth

ptr07

E function as sth

gmatgmat

3x

cold2100

我选了D,正确答案是E???

我是鱼

function as sth