It is possible that, [bgcolor=yellow][bgcolor=#ffffff]like the Volkswagen[/bgcolor], whose unchanging exterior over decades concealed many changes in its internal machinery, the evolution of many prehistoric microbes occurred with no significant modification to their sheaths.
(A) the evolution of many prehistoric microbes occurred with no significant modification to their sheaths
(B) the evolution of many prehistoric microbes was occurring without significant modification of their sheaths
(C) no significant modification was made to the sheaths of many prehistoric microbes as they were evolving
(D) the sheaths of many prehistoric microbes went without significant modification during their evolution
(E) many prehistoric microbes evolved without significant modification of their sheaths