Leslie Lewes, age 12, of Salt Lake City, Utah, for he question:

What exactly is plankton?

The sea is the home of countless animals, huge fish, small fish and every size between. Most of these fellows are meat-eaters and larger fish dine on smaller fish. But the smallest fish must also eat. The sea itself provides these little fellows with her own nutritious seafood salad, which is plankton. Plankton is so good that many larger fish ding on it also.

Seawater teems many tiny mites too small for our eyes to see. There are fish eggs and glassy midgets of larva fish. There are bacteria and little water flea crustaceans. There are also bits of floating plant life, algae and dainty diatoms. Mixed together this floating food is plankton. It is there, free for the taking in large quantities.

Plankton is so nutritious that it supports the largest animal the world has ever known. The blue baleen whale lives by sifting tons of plankton from the water every day.