| Title | Comment | Keywords |
|---|---|---|
| Life on Land | 10:50 - 12:11 (01:21) / 1.4 MB | "Dee Trent", life, atmosphere, oxygen, photosynthesis, stromatolite, algae, ozone, "carbon dioxide", "solar radiation", Precambrian, Paleozoic, limestone, ocean, horse, camel, humans, sycamore, "carbon cycle" |