Engineers design structures such as bridges and dams to help society run smoothly. They also use science to create inventions such as light switches and toilets that make life easier. Engineering Answers takes a closer look at these and other objects, exploring how they work and why they are important. Kids Core is the must-have line of nonfiction books for supporting the Common Core State Standards for grades 2-5. Kids Core Features: A wide variety of high-interest topics, Well-researched, clearly written information text, Primary sources with accompanying questions, Multiple prompts and activities for writing, reading, and critical thinking, Charts, graphs, diagrams, timelines, and maps.