Phyllis Santos, age 8, of Erie, Pa., for her question:

WHAT MAKES BLOOD RED?

Hemoglobin is the name of the pigment in blood that colors it red. Hemoglobin is located in the red blood cells.

When the red cells pass through the "alveoli" or air sacs of the lungs, they take up oxygen. The hemoglobin in them combines with the oxygen to form a compound called oxyhemoglobin.

When the red cells travel through the rest of the body, they give up the oxygen to the tissues. In the tissues, the hemoglobin takes up carbon dioxide and releases it in the alveoli of the lungs.

Hemoglobin is a complex molecule that includes iron and a protein called globin.

Anemia may result from a storage of hemoglobin or from hereditary abnormalities in the blood's hemoglobin.