The Circulatory System: Why Does My Heart Beat? (Body Systems)

What does your heart do? What makes the sound of your heartbeat? Why does your body need blood? Your body is amazing! There are parts you can see and parts under your skin that you can't see. These parts work together to keep you alive and help you to do incredible things. You can feel your heart beating in your chest. Have you ever wondered why it does? Read this book in the 'Body Systems' series to find out!