Dan Mellinger, age 10, of Lancaster, Pennsylvania, for his question:

Where do weeds come from?

Dan pulls up all the weeds in his garden on Saturday    and by the next Saturday, to and behold, another crop of weeds. This sort of thing tends to take the happy fun out of gardening and change it into a tiresome chore. Too bad. But the fun comes back, even more so, when we understand what weeds are all about. For millions of years, they were the only small plants in the world. The earth helped them to thrive and strive to be here when at last the human family arrived on the earth.

Mankind the farmer chose the most useful little plants    and gradually made them better. In time they became our big beautiful crop plants and flowers. But their wild relatives stayed around, shedding their weedy seeds in the ground every season. Lots of these seeds are meant to feed the charming birds and other little wild creatures. A few sprout new generations in the fields and some sprout up in our gardens. When they crowd out our flowers and vegetables, it's time to uproot them. But for goodness sake let's not try to wipe out all the weeds in the world. Someday we may adopt some more and improve them to create a long list of new plants for our fields and gardens.