she had done this on her tenth birthday , and it had struck her then , that each little seed would still be somewhere after several days ; and later it struck her that although they would eventually disappear , each one would set in motion other events , and be transformed into other things ; for example , some might give rise to new dandelions , which would in turn spread their own seeds , and others might become food for worms , which would in turn be food for birds , and so on .