大全987-18

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

and 表示并列,yet表示转折

beating in unison 指cells一起跳动

adopting specialized orientations exclusive of one another 强调的是cell之间的不同

所以两个成分不应该是并列，而是用表转折的连词yet连接

...我是这样理解的