Photosynthesis
Photosynthesis is the biological process by which plants, algae, and certain bacteria convert light energy into chemical energy, producing oxygen as a byproduct and forming the foundation of most life on Earth.
During photosynthesis, chlorophyll in plant cells absorbs sunlight and uses that energy to convert carbon dioxide and water into glucose, a sugar that provides energy for the plant, while releasing oxygen into the atmosphere.
This process is believed to have evolved in early photosynthetic bacteria over two billion years ago, dramatically transforming Earth's atmosphere by introducing oxygen and enabling the evolution of complex, oxygen-dependent life.
Photosynthesis remains essential to virtually all ecosystems today, forming the base of most food chains and playing a critical role in regulating the planet's carbon cycle and climate.