Theme: Nonfiction. Phonics Skill: Prefixes. Everyone gets sick sometimes. On the outside, symptoms can make a person feel terrible. On the inside, the body's immune system is working to beat the cause of the illness. How can we make sure our immune systems are as strong as possible? Support striving readers with these low-level, age-respectful decodable books. Phonics Decodable Readers feature words from basic phonics rules, plus specific pattern words. All books feature a glossary, and nonfiction books include technical vocabulary and definitions to help set striving readers up for success. Each book is 48 pages.