Maureen Kenney, age 11, of Youngstown, Ohio, for her question:

How many oceans are there?

The number of oceans depends on how we partition them. We can count the vast Pacific as one or divide it at the equator into the North Pacific and the South Pacific. We can count the Atlantic as one or use the equator to divide it into the North Atlantic and the South Atlantic. The Indian Ocean counts as one and so does the Arctic Ocean that covers the North Pole. The Indian, Atlantic and Pacific oceans reach down to the south polar region, where they swirl around the land mass of Antarctica. These mingling waters may be called the Antarctic Ocean. This gives us a total of seven oceans and each ocean has a quota of smaller seas. However, there are no natural dividing lines between them. Actually, all these oceans are linked together and their waters mix and mingle around the entire globe. So in reality, the earth has only one world wide ocean. This explains why DDT from our rivers is found in the tissues of Antarctic penguins.