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 |
|---|---|---|---|
| 274808 | 2020-08-20 10:01:08 | 115.45 | 99% |
| 272124 | 2020-07-24 03:38:49 | 113.20 | 98% |
| 270917 | 2020-07-04 03:25:54 | 122.36 | 99% |
| 269669 | 2020-06-18 09:42:00 | 120.98 | 98% |
| 267955 | 2020-05-23 11:18:46 | 115.10 | 98% |
| 266745 | 2020-05-10 09:33:38 | 104.89 | 97% |
| 260827 | 2020-03-08 04:59:07 | 120.71 | 98% |
| 259134 | 2020-02-15 01:07:58 | 115.75 | 99% |
| 256396 | 2020-01-04 01:23:09 | 117.87 | 98% |
| 251371 | 2019-09-16 11:49:26 | 117.90 | 98% |
| 240811 | 2019-06-02 05:52:31 | 130.18 | 99% |
| 235989 | 2019-05-02 10:03:46 | 112.26 | 98% |
| 229665 | 2019-03-28 08:58:38 | 128.20 | 99% |
| 225447 | 2019-03-05 01:09:09 | 116.22 | 98% |
| 219261 | 2019-02-02 03:33:31 | 126.29 | 99% |
| 213200 | 2018-12-24 22:28:26 | 103.83 | 97% |
| 208009 | 2018-12-01 00:26:19 | 113.83 | 97% |
| 205424 | 2018-11-23 04:41:30 | 122.90 | 99% |
| 205403 | 2018-11-23 04:24:00 | 113.26 | 98% |
| 203409 | 2018-11-13 08:26:35 | 121.74 | 98% |
| 202927 | 2018-11-09 09:15:53 | 107.60 | 97% |
| 196391 | 2018-10-14 21:40:30 | 116.62 | 97% |
| 194376 | 2018-10-04 07:28:12 | 119.26 | 98% |
| 193088 | 2018-09-28 03:23:02 | 113.46 | 98% |
| 183735 | 2018-08-14 07:14:39 | 112.67 | 98% |
| 183637 | 2018-08-13 02:18:28 | 110.11 | 98% |
| 182340 | 2018-08-05 05:59:00 | 102.63 | 97% |
| 181427 | 2018-08-01 05:00:52 | 119.72 | 99% |
| 180720 | 2018-07-28 09:16:51 | 116.82 | 98% |
| 179316 | 2018-07-24 07:18:38 | 112.41 | 98% |
| 166111 | 2018-05-04 02:17:46 | 114.08 | 98% |
| 164202 | 2018-04-17 15:18:48 | 113.95 | 99% |
| 160801 | 2018-03-23 23:41:08 | 117.71 | 99% |
| 159615 | 2018-03-16 06:23:38 | 101.31 | 97% |
| 158099 | 2018-03-03 04:55:45 | 108.71 | 98% |
| 155642 | 2018-02-12 11:35:16 | 116.31 | 99% |
| 139164 | 2017-10-22 22:56:06 | 102.82 | 98% |
| 138500 | 2017-10-21 07:43:40 | 104.22 | 97% |
| 134977 | 2017-10-10 03:33:05 | 110.18 | 98% |