

Red Blood Cells- Resembles a donut. It is shapes like a disk. Carries oxygen to the tissues and removes carbon dioxide. Also called erythrocytes. (World Book, 2001)
percent water. It makes 50 to 60 percent of blood. (World Book, 2001), (Wikipedia Contributors, 2006)
The Circulatory system- The Circulatory system consists of the heart, a vast network of blood vessels, and blood itself. (World Book, 2001)