Apeculiarfeatureoftheembryonicmammaliancirculatorysystemisthatintheareaoftheheartthecellsadheretooneanother,beatinginunisonandadoptingspecializedorientationsexclusiveofoneanother.（）
(A)beatinginunisonandadopting
(B)theybeatinunisonwhileadopting
(C)beatinunison,andadopt
(D)beatinginunisonyetadopting
(E)eventhoughtheybeatinunisonandadopt