What is the main difference between the two hypotheses for the origin of the eukaryotic cell?

Question

Quizplus · Accepted Answer

The main difference between the two hypotheses for the origin of the eukaryotic cell is that one hypothesis (endosymbiotic theory) suggests that engulfment of a proteobacterium occurred before formation of the nuclear envelope, while the other hypothesis (symbiogenesis theory) suggests that engulfment occurred after formation of the nuclear envelope. Both hypotheses involve the conversion of a proteobacterium to a mitochondria, and neither suggests that eukaryotic cells evolved from an archaeon rather than a bacterium. The only difference is the timing of the engulfment event in relation to the formation of the nuclear envelope. Therefore, the best choice is D.

What Is the Main Difference Between the Two Hypotheses for the Origin