Cindy Walser, age 73, of Thomasville, N.C., for her question:

WHAT MAKES THE OCEANS SALTY?

More than 70 percent of the world's surface is covered by oceans. Nature has elected to make all of this seawater salty.

Most of the salty material in the sea, which amounts to about 3.5 percent, is common table salt. All of the elements that make up the earth's crust, such as calcium, sulfur and magnesium, are also found in the waters of our oceans.

In comparing the composition of seawater with the composition of the body fluids that are in man, scientists have discovered that the chemical proportions of the two liquids are very much alike. It seems to give some support to the scientific theory that all life began in the sea.