Which Step Is Thought to Have Occurred, According to Endosymbiotic

Multiple Choice

Which step is thought to have occurred, according to endosymbiotic theory?

A) A dependent prokaryotic cell was engulfed by an independent prokaryotic cell, allowing the dependent cell to survive within the independent host cell.
B) A dependent prokaryotic cell was engulfed by another dependent prokaryotic cell, allowing each cell to survive with the help of the other.
C) An independent prokaryotic cell was engulfed by a dependent prokaryotic cell, allowing the dependent host cell to survive with the help of the engulfed cell.
D) An independent prokaryotic cell was engulfed by another independent prokaryotic cell, after which the engulfed cell lost certain functions and became dependent on the host cell.
E) An independent prokaryotic cell was engulfed by another independent prokaryotic cell, and both continued activities independent of one another.