The correct answer is A. The theory that complex cells evolved after primitive cells engulfed bacterial cells that continued functioning.
Explanation:
This diagram shows how a primitive cell or a cell containing only genetic material evolves into a complex cell with specific organelles such as chloroplast or mitochondria by engulfing or integrating other cells, especially prokaryotic cells that continue living in the primitive cell and become specialized organelles. This process supports the theory the evolution of cells was possible as simple cells engulfed bacteria because as the diagram shows the engulfed bacteria evolved into organelles that make the cell become more complex as there were specific structures in the cell for different functions.
