Which of the following is true of secondary endosymbiosis?
It is indicated by the presence of a double membrane surrounding the endymbiont.
An organism containing one endosymbiont engulfs another organism, and that organism becomes an endosymbiont.
It is indicated by the presence of a nucleomorph.
An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont.
It is indicated by the presence of a mixotroph.