1. human respiratory system, oxygen transport in blood, vertebrate lungs, comparative anatomy 2. infectious diseases, pathogens (viruses, bacteria, others), hygiene practices, disease prevention 3. chemical reaction indicators, temperature/color change, accurate measurement, data interpretation 4. physical changes, boiling vs evaporation, phase reversibility, thermal conductivity of materials 5. force diagrams, applied/friction/gravity/normal forces, motion analysis, mass vs weight, Moon gravity 6. electrical circuits (symbols, parallel setup), soil composition (gravel, sand, clay, humus), Solar System model, puberty changes