Debra Burr,  age 8, of Indianapolis, Ind., for her question:

What is kelp?

It grows in the sea like a tangled forest of brown rags. We do not often See kelp while it is alive and growing. But almost every day We use things that are made from this kelp seaweed. One substance from kelp is used in the making of chocolate mills, salad dressing, ice cream and even aspirin tablets. Another gives us iodine.

Kelp is a raggedy brown seaweed. It grows in shallow water near the shore, rocking to and fro with the tossing tides. The very long water weeds seem to be rooted to the ocean floor, and its tough, brown rags trail up through the water. The trailing rags may be 200 feet long, which is as tall as 34 tall men.

It grows in masses like dense thickets, but kelp is a very different plant from the shrubs and bushes that grow on land. It is an alga, and the algae are the simplest plants in the world. It has no true roots or stems or leaves. Like all plants, it is made of boxy little cells. But the different cells of a corn plant do different jobs. The root cells, leaf cells and stem cells cannot change jobs.

Any little ceii in an alga plant can do the work of a root, a leaf or a stem. The cells that hold down the keip are acting me roots, but they are not true roots. The cells In the long, stringy stem can do the work of roots or leaves. The wide, broom rags along the stringy thread are not true leaves, though they look and work like leaves.

Every cell in a kelp plant is stuffed with green chlorophyll. A brown material hides it, but it works like the chlorophyll in all green leaves. It uses sunlight to make plant food from water and carbon dioxide. The kelp also soaks up all kinds of rich minerals from the salty sea. Its tangled rags are harvested from the ocean, and these minerals are used to make all kinds of useful things.

Sometimes the kelp is burned, and a mineral caiied sodium iodide is taken from the ashes. This mineral gives US iodine. A substance called algin also comes from kelp, and align has a sticky trick. It can hold other substances together. Align is used to make ice cream and chocolate milk, creamy puddings and smooth salad dressings.

Kelp plants like to grow in water that is cool, but not cold. Beds of kelp grow off the shores of Ireland and Scotland. Here the northern seas are warmed slightly by the Gulf Stream, which has traveled thousands of miles up from the tropics. Kelp also grows along our Pacific shores, and whole forests of kelp grow in the waters that wash around the islands of Japan.