ix Activities Reinforce and Extend Learning Summary feature provides an additional review tool for you and reinforces key learning objectives. Check Your Understanding review questions allow you to demonstrate knowledge, identification, and comprehension of chapter material. Critical Thinking questions develop higher-order thinking and problem-solving skills. Core Skills activities link chapter content to various academic subjects and to career expectations in the areas of reading, writing, and speaking. STEM Connections reinforce STEM-related content through math, science, and technology activities. Chapter Experiments provide step-by-step instructions and allow students to draw conclusions based on text content and observations.