Answer: Plasma membrane
Explanation:
According to endosymbiont theory most of the membrane bound cell organelles like nucleus, Golgi bodies, and endoplasmic reticulum are originated from plasma membrane in the deep folds. This theory also suggests that chloroplast and mitochondria are originated from the bacterial cells or primitive prokaryotic cells. These are the organelles chiefly present in the eukaryotic cells. This theory suggests that primitive earth was supported by the bacteria.
