Cambridge Discovery Education Interactive Readers are the next generation of graded readers - captivating topics, high-impact video, and interactive exercises designed to motivate and engage. Skin: it covers us, we decorate it, it can tell us if we're healthy or not. Learn about our biggest and most visible organ, and how we can protect it. Use your unique code inside the book to access the online reader, complete with videos and interactive exercises. Word count: 2891. Lexile Reading Level: 1060L.