Discover the main systems of our amazing human body with this new series of books! The blood that flows through your body constantly brings food and oxygen to your muscles, organs, and bones and carries away waste. And it is all powered by that magnificent muscle, your heart. Did you know that your heart beats about 100,000 times a day? Or that the blood in your body travels a total of 12,000 miles daily? That's more than four times the width of the United States from coast to coast! Learn all this and more in Circulatory System. ABOUT THE SERIES: The human body is a complex ⹀ and remarkable ⹀ machine. Digesting our food. Pumping our blood. Walking, running, and dancing. It takes our many body systems working together to keep us alive and living our lives to the fullest. This set of A True Books offers an in-depth look at our amazing bodies ⹀ one system at a time. Interesting information is presented in a fun, friendly way ⹀ and in the simplest terms possible ⹀ giving students a "behind-the-scenes" look at how their bodies work.