What are vertebrates? Which primate can fit in the palm of your hand? What do a cat and a fish have in common? In this book, readers are introduced to Fluffy the cat. Learning about Fluffy's family tree helps them to discover how different animals are grouped and classified. Each book in this series provides superb coverage of a science topic with an interesting twist. An exciting, real-life application makes the topic fun, accessible, and shows readers why science matters.