Mike Cullinan, age 12, of Schenectady,N.Y., for his question:

WHERE DO WE GET OXYGEN IN WINTER?

Many readers ask this logical question. But as you know, Andy can select only one for the column. So if you asked this same question, please don't feel sad or mad. You can ask as many more questions as you wish and, who knows, maybe one of them will be selected.

We are told that green plants pour fresh oxygen into the air every day, but in winter much of our greenery departs. However, the vast evergreen forests continue to supply oxygen, and the winds continue to spread it around the world.  Meantime, the seas teem with microscopic algae. These tiny seaweeds add countless tons of oxygen to the air. Actually they out produce all the land plants and go on producing all through the year.