HOMOLOGOUS STRUCTURES-suppose EVOLUTION is to be compared to a Mountain with different peaks, and the higher we go on the mountain the greater is the complexity. Suppose you're already halfway up there, and suddenly realise while standing on the vantage point that there's a a better route! But you can't climb all the way down and start afresh, because that's just not evolution, as it has no foresight, and you'll have to make do with whatever you've got. "