This worksheet is designed to provide a beneficial enhancement to fourth-grade students' comprehension skills in the realm of nonfiction. The focus is on identifying the primary idea and specific details within a text. Students will be required to read a brief nonfiction passage and use red underlining to highlight the main idea and blue underlining to mark supporting details. By doing so and completing the accompanying chart, young readers will not only acquire fascinating information about lungs but also further develop their abilities in reading and writing.