The primary product of photosynthesis is glucose. During this process, plants, algae, and some bacteria convert sunlight, carbon dioxide, and water into glucose and oxygen. The glucose serves as an energy source for the plant and can be transformed into other carbohydrates. Oxygen, the byproduct, is released into the atmosphere, which is essential for the survival of most living organisms. This process plays a crucial role in the Earth's ecosystem, maintaining the balance of gases and providing energy for the food chain.