Arrange the events in the order they would have occurred according to the theory of endosymbiosis.

Endosymbiotic thoery explains how eukaryotic cells originated or emerged from prokaryotes. According to this theory some eukaryotic cells such as chloroplasts and mitochondria arose from a symbiotic relationships that existed between two prokaryotic cells.  In this question, the order of events as they would have occurred according to this theory would be; 
1. Large and small prokaryotes existed together
2. Large prokaryotes engulfed smaller prokaryotes
3. Both varieties of prokaryotes began living symbiotically
4.  Lastly the mitochondria and the chloroplast evolved from prokaryotes.