Which theory tries to explain the origin of endoplasmic reticulum nuclear membrane?

Answer 1

The theory of endosymbiosis which believes that nuclear membranes and organelles such as the mitochondrian have evolved from a semi"mutation" in which a prokaryotic cell was engulfed by a eukaryotic cell and instead of being digested it survived and has evolved into key features of the eukaryotic cell. Evidence for this is the fact that the mitochondrian have their own ribosomes ( of which are the prokaryotic variety) and their own DNA which allow them to make their own proteins that can be used in synthesis of adenosine triphosphate (ATP)

Answer 2

The endosymbiotic theory proposes that the endoplasmic reticulum and nuclear membrane originated from the infolding of the cell membrane of ancient prokaryotic cells that formed a symbiotic relationship with ancestral eukaryotic cells. This theory suggests that the endoplasmic reticulum and nuclear membrane evolved from these primitive intracellular membranes.