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 |
|---|---|---|---|
| 284437 | 2019-03-03 00:42:47 | 122.71 | 97% |
| 282391 | 2019-02-25 01:51:56 | 140.69 | 98% |
| 282390 | 2019-02-25 01:50:48 | 127.17 | 97% |
| 279102 | 2019-01-08 01:42:26 | 129.51 | 98% |
| 277952 | 2019-01-07 02:22:28 | 133.66 | 97% |
| 274942 | 2018-11-23 04:41:20 | 145.49 | 97% |
| 252246 | 2018-09-06 04:36:49 | 119.28 | 95% |
| 248904 | 2018-08-31 21:58:10 | 132.70 | 97% |
| 248903 | 2018-08-31 21:56:57 | 121.02 | 97% |
| 245784 | 2018-08-27 23:28:34 | 113.38 | 96% |
| 243764 | 2018-08-25 22:57:52 | 132.68 | 97% |
| 237361 | 2018-05-13 08:14:01 | 131.92 | 97% |
| 237191 | 2018-05-12 21:54:52 | 175.47 | 99% |
| 221800 | 2018-01-15 22:14:13 | 107.45 | 96% |
| 221799 | 2018-01-15 22:12:51 | 98.86 | 95% |
| 221383 | 2018-01-14 00:48:54 | 106.58 | 96% |
| 221382 | 2018-01-14 00:47:23 | 101.25 | 96% |
| 220079 | 2018-01-12 02:51:52 | 134.32 | 98% |
| 220078 | 2018-01-12 02:50:41 | 136.35 | 98% |
| 215760 | 2017-12-17 09:38:20 | 126.56 | 97% |
| 213238 | 2017-12-08 22:48:47 | 138.26 | 98% |
| 204176 | 2017-11-19 19:22:29 | 131.61 | 98% |
| 200266 | 2017-10-31 03:34:07 | 117.01 | 97% |