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. Sharks, ghosts, aliens, snakes...cell phones? All kinds of things make people afraid. How does our brain tell us to be afraid, and can we control fear? Use your unique code inside the book to access the online reader, complete with videos and interactive exercises. Word count: 2480. Lexile Reading Level: 820L.