Talk:Another World/@comment-25558572-20140728001408/@comment-25403255-20150223210341

Well, when the people of the planet that we are introduced to in the beginning of the story (not to be confused with our plant earth) were invaded by a different reality, the plant life got infected. This infection would cause all plants that produce oxygen from photosynthesis to be altered in a way so that they instead spread the alternate reality's breathable gas, which is bad for the people who were invaded. If it is inhaled for a certain amount of time, it will cause it heart attack thus killing the entire human race of that reality, unless they invade a reality similar to theirs. This ended up being our reality in which we have named our planet, Earth. Hope this helped.