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 |
|---|---|---|---|
| 32526 | 2019-12-21 10:29:30 | 119.98 | 97% |
| 29638 | 2019-08-27 09:20:20 | 127.13 | 98% |
| 28848 | 2019-08-07 19:41:56 | 131.83 | 98% |
| 23676 | 2019-05-12 16:41:46 | 127.22 | 98% |
| 16631 | 2019-03-08 23:13:56 | 122.57 | 99% |
| 13915 | 2019-02-21 06:19:29 | 133.32 | 99% |
| 6665 | 2018-11-29 23:12:46 | 122.81 | 99% |