Plant leaves are essential parts of a plant that primarily function in photosynthesis, the process by which plants convert sunlight into energy. Leaves come in various shapes and sizes, depending on the type of plant. They typically have a flat surface to maximize sunlight absorption and contain chlorophyll, the green pigment that captures light energy. In addition to photosynthesis, leaves also play a role in gas exchange. Tiny openings called stomata allow carbon dioxide to enter and oxygen to exit. This process is vital for maintaining the balance of gases in the atmosphere and supporting life on Earth, including that of humans and animals.