In the Franchthi cave in southern greece 14 thousand years ago, there is evedence that humans there were domesticating snails. The shells found there where larger then most snails, suggesting that they were being sulectivly breeded. What would be the effects if this practise survided and became more widespread? How big, after thousands of years of selective breeding, could one grow a snail? Have fun. (sorry if this seems trivial)