    SeatenceT Whi addiooal sembrans ‘Jo sendy chlorplss    Sentence 2; White. pritnary. chloroplasts’ hive. a, double rhembraine  fromn, their cyanobacterial ancestor, secondary’ chloroplasts “have  additional membranes outside of the-original fo; is a result of the  secondary ' endosymbiotié event, when a rionphotosynthetic  cokaryote engulisd a. diloroplast-containing alga but failed to digest  it—miuel like the cyanobacterium at the beginning of this Story.