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 |
|---|---|---|---|
| 19945 | 2019-10-19 10:05:48 | 89.30 | 99% |
| 19406 | 2019-09-25 13:07:09 | 77.63 | 96% |
| 18243 | 2019-08-18 10:50:47 | 77.16 | 96% |
| 10121 | 2019-04-28 12:34:41 | 70.49 | 97% |
| 7144 | 2019-03-03 13:01:56 | 70.81 | 96% |
| 2852 | 2018-12-05 08:55:18 | 67.19 | 96% |