1. The documents discuss photosynthesis, explaining that it is the process by which plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. 2. It describes the light reactions and Calvin cycle, noting that the light reactions produce ATP and NADPH using energy from sunlight which is then used to fix carbon in the Calvin cycle. 3. The documents focus on explaining why plants are green, noting that chlorophyll a absorbs mostly blue and red light while reflecting green light, making plants appear green.