Explain the endosymbiotic theory of the origin of eukaryotic cells.

Endosymbiosis is universally accepted to have played a major role in the evolution ofeukaryotes (most obviously, in the origin of cellular organelles such as mitochondria and plastids), but genomic analyses have given rise to the hypothesis that the originevent itself was a symbiotic merger of two (or more) cells. why the fudge did u block me? 

Idk