1. Photosynthesis and Carbon Sequestration: Increased photosynthesis due to rising CO₂ levels, measurement of global photosynthesis using carbonyl sulfide, and role of forests as carbon sinks. 2. Plant Physiology and Gas Exchange: Stomatal response to increased CO₂, effects on leaf toughness and insect feeding, and the impact of light intensity on plant gas exchange. 3. Enzyme Activity and pH Effects: Catalase activity in hydrogen peroxide breakdown, effect of pH on reaction rate, and experimental control of abiotic factors. 4. Kidney Function and Filtration: Structure and role of nephron parts, glucose reabsorption, ADH influence on water retention, and urine concentration changes during dehydration. 5. Mutation and Genetic Variation: Impact of single base mutations on protein synthesis, differences in mutation rates during mitosis and meiosis, and mutation rate calculations. 6. Nitrogen Cycle and Agricultural Impact: Processes of nitrification, denitrification, and nitrogen fixation, nitrate pollution in rivers, and correlation between fertilizer use and water quality.