大全－18，不是考平衡结构吗？

     A peculiar feature of the embryonic mammalian circulatory system is that in the area of the heart the cells adhere to one another, beating in unison and adopting specialized orientations exclusive of one another.

(A) beating in unison and adopting

(B) they beat in unison while adopting

(C) beat in unison, and adopt

(D) beating in unison yet adopting（D）

(E) even though they beat in unison and adopt

为什么beat和adopt不是和前面的adhere平衡？