Themes: Drones, Technology, Nonfiction, Tween. Whether large or small, unmanned drones are used in some interesting ways by both the military and private sector, from spying to firefighting to protecting endangered animals. Red Rhino Books Nonfiction is the first Hi-Lo children's nonfiction series at a first-grade reading level for students in grades 4–7. Visually appealing fullcolor photographs and illustrations—along with fun fact boxes—keep these books flowing. Also includes prereading comprehension questions along with a 20-word glossary for further reading support.