The Level I Biology Student Textbook is an elementary text for grades 4-6 that introduces students to the scientific discipline of biology. Students will learn about classifying living things, cells and their structures, plants and photosynthesis, single-cell organisms, life cycles of butterflies and frogs, and ecosystems. Level I Biology expands on concepts introduced in the Pre-Level I Student Textbook and also covers additional biology concepts. The Level I Biology Student Textbook has 10 full-color chapters.