Your amazing human body comes complete with a full set of systems that work together to make you. How Your Body Works introduces the marvels of the human body and unlocks some basic mysteries, such as why blood is red, why you couldn't hear without tiny hairs, why parts of your bones look like sponge, why your brain is even better than the fastest computer, why your lungs could cover a tennis court, and why your small intestine is actually as long as a bus. A clear, straightforward style captures and holds the interest of young readers to instill a lifetime of wonder. Inside your chest, a set of expandable bags helps keep your heart pumping and your blood moving. As the main part of your respiratory system, your amazing lungs pull in oxygen and push out poisons and germs to keep you healthy.