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 |
|---|---|---|---|
| 15327 | 2020-01-04 04:56:16 | 123.64 | 98% |
| 12876 | 2019-05-07 07:39:08 | 125.22 | 99% |
| 11666 | 2019-01-31 03:30:27 | 115.52 | 98% |
| 9217 | 2018-10-18 04:55:00 | 124.40 | 98% |
| 4556 | 2018-05-21 20:55:08 | 106.05 | 99% |
| 4527 | 2018-05-15 16:56:19 | 105.47 | 99% |