ELI5: We say that only some planets can sustain life due to the “Goldilocks zone” (distance from the sun). How are we sure that’s the only thing that can sustain life? Isn’t there the possibility of life in a form we don’t yet understand?
ELI5: Why is The Beatles’ Sergeant Peppers considered such a turning point in the history of rock and roll, especially when Revolver sounds more experimental and came earlier?
ELI5: Why does Romaine seem to be recalled so frequently, but other lettuces not so often? Is there something about romaine that doesn't occur with green leaf, spinach, etc..?