Big Idea: Our Healthy World is an expository nonfiction text organized in three chapters that cover meeting our basic needs (such using natural resources to make our lives more comfortable and renewable and nonrenewable resources), using natural resources (such as natural resources for products and energy), and conserving natural resources (such as making less garbage and protecting natural resources). Each two-page spread is linked to a big idea, such as “We can take care of Earth’s natural resources.” Each chapter concludes with two activities written in procedural language, and a final activity challenges students to “think like a historian.”