Holt Science - Grade 6 Author:Joan Wade Fossaceca, Joseph Abruscato, Jack Hassard, Donald Peck Sixth Grade General Science Textbook — 6 main units with 3-4 chapters within each unit — MAIN UNITS COVERED [and a few sub-units] — 1. Motion and energy — 2. The changing earth — 3. Matter and its changes — 4. Human body systems — --food and nutrition — --digestion and circulation — --respiration and excretion — --taking care of yourself — 5. The earth's r... more »esources