Oxygen was initially created in earth's atmosphere by
●volcanoes outgassing
●cyanobacteria photosynthesizing
●greenhouse effect
●ozone breaking down

Tanya was used to using word, and she did some work for her brother mike, who was using wordperfect. tanya was quickly able to use wordperfect for windows with little difficulty, since many of the commands for it were the same as the commands for word. tanya's ability to use wordperfect best illustrates:

If we can't separate our civilized self from our savage self which will take over and why

The most heavily populated areas of africa are found