Raymond Anderton, Age 11, Of Peterborough, Ont., Can., for his question:

Why is blood red?

The blood stream which circulates through the body is a pale liquid. Swats of tiny blood cells float along in every drop of the liquid  and most of these blood cells are red. They are too small for our eyes to see. But under the microscope, a red blood cell looks somewhat like a round saucer with a thickened rim and a dent in the center.

Each is a sac filled with a red red substance called hemoglobin. A drop of blood is red because it is crowded with millions of these floating red cells.