IMO D....they beat in unison,yet adopt diff orientions..clearly defines the idea that cells beat together but they have diff orientations...So clearly showing contrast.
A) beating in unison and adopting - It shows some added info to chrac of cells , while it s not added, it is contrast.
(B) they beat in unison while adopting - no parllelism
(C) beat in unison, and adopt - same as A
(D) beating in unison yet adopting
(E) even though they beat in unison and adopt - Even though is wrong and parellism.
So, clearly D.
A) beating in unison and adopting - It shows some added info to chrac of cells , while it s not added, it is contrast.
(B) they beat in unison while adopting - no parllelism
(C) beat in unison, and adopt - same as A
(D) beating in unison yet adopting
(E) even though they beat in unison and adopt - Even though is wrong and parellism.
So, clearly D.












