It's like in high school where when we were studying origins of life, there were three main models we were introduced to,
Primordial Soup Model
Extra-terrestrial
And then one other one that was like intelligent design, I'm not sure if it was called that though
We only went into depth on the first one, but they still mentioned the others because they are still out there. I mean, they still mention perpetual motion even though they pretty much laugh it off as impossible.