Eldon Hemminger, age 11, of Winnipeg, Man., Canada, for his question:

WHAT ARE ROTIFERS?

Pond of still water may look perfectly clean and clear, but chances are it is populated with a multitude of tiny creatures, too small to see. Some of them will be rotifers. Magnified under a microscope, they look like chubby little tree trunks, each crowned with a circle of whiskery branches. Actually the branches are busy little feelers called cilia, sweeping the water for mini fragments of food.

The tiny mouth is in the center of the circle of cilia. From there the food goes down to be digested inside the trunk. A rotifer also uses his cilia to swim around. Male and female rotifers sometimes unite to produce offspring. However, the female rotifer can produce little ones all by herself.