- Respiration
- Digestion
- Photosynthesis
- Fermentation
Photosynthesis occurs in chloroplasts, where chlorophyll absorbs sunlight to convert CO₂ and water into glucose and oxygen. The process involves light-dependent reactions (capturing energy) and the Calvin cycle (synthesizing sugars). It sustains autotrophs and oxygenates Earth’s atmosphere, forming the base of most food chains.
