The purpose of this investigation is to give students an opportunity to use the disciplinary core idea adaptation and the crosscutting concept of cause and effect to figure out, Why do mammals that live in the Arctic Ocean have a thick layer of blubber under their skin? Students will also learn about how scientists use different methods to answer different types of questions during the reflective discussion. The Teacher Notes provide connections to the standards, a timeline, safety notes, information on materials and preparation, and step-by-step instructions for facilitating the lesson and assessing student outcomes. After the Teacher Notes, you will find classroom-ready reproducible pages in the form of an Investigation Handout and Checkout Questions. Before you begin the lesson, we recommend reading Chapters 1 and 2, which are in this book selection Chapter 1 provides an overview of Argument-Driven Inquiry (ADI) with an explanation of what happens during each of the eight stages of ADI, which are the same for every ADI investigation. Chapter 2 focuses on the investigations and how to use them, not to replace an existing science curriculum, but rather to function as a tool that teachers can use to integrate three-dimensional instruction into their existing curriculum. Also included in the book selection are the Table of Contents, Preface, Acknowledgments, About the Authors, Introduction, and Index.