Tom Hartnett, age 14, of Scotland, South Dakota, for his question:

Why is the Black Sea so named?

The Romans called it the Friendly Sea and its outline might suggest calling it the Kidney Sea. It nestles north of the Mediterranean, surrounded by Turkey and Russia and several middle European countries. This is a region where the winter cli¬mate is given to cold rains and damp fogs. When these dark, heavy fogs settle on the waters of the Black Sea, they shut out the light and warmth of the sunny sky and even the middle of the day seems almost as dark as night. Fishermen on its waters often get lost in these blanketing fogs. This is how the Black Sea got its name.

The foggy, dark sea is about the size of California and its surface waters teem with herring and mackerel and many other edible fishes. But its plant and animal life does not descend below 300 feet. This is because the lower levels of the Black Sea are unruffled by turbulence and hence very short of oxygen. The deepest levels of its lifeless waters dip down to 7,000 feet.