Mitochondria and chloroplasts display similarities with bacteria that led to the endosymbiont theory. This theory states that an early ancestor of eukaryotic cells engulfed an oxygen-using non-photosynthetic prokaryotic cell. Eventually, the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an endosymbiont, a cell living within another cell. Indeed, over the course of evolution, the host cell and its endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion. At least one of these cells may have then taken up a photosynthetic prokaryote, becoming the ancestor of eukaryotic cells that contain chloroplasts.
| Game | Time | WPM | Accuracy |
|---|---|---|---|
| 23287 | 2020-09-09 01:34:23 | 69.25 | 95% |
| 17406 | 2020-06-21 06:07:21 | 75.10 | 95% |
| 15528 | 2020-05-21 18:30:10 | 73.00 | 96% |
| 15398 | 2020-05-21 03:49:41 | 71.31 | 95% |