The Endosymbiosis Theory and Eukaryotesc In the origin of the eukaryotes, endosymbiosis
a) is thought to explain the origin of the nucleus.
b) describes the engulfing of a photosynthetic bacterium that ultimately gave rise to the mitochondria
c) most likely began with a free-living prokaryote entering the cell as undigested prey
d) most likely began with a viral infection of the host cell