What is the main purpose of photosynthesis?

The main purpose of photosynthesis is to convert sunlight into chemical energy, providing food for plants and oxygen for the atmosphere. During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. The glucose serves as an energy source for growth and reproduction, while oxygen is released as a by-product. Photosynthesis is critical for life on Earth, as it forms the base of the food chain and regulates atmospheric gases. Forests, grasslands, and marine phytoplankton are major contributors to this life-sustaining process.