Leaves are the primary location for photosynthesis, the process by which plants produce food using sunlight, carbon dioxide, and water. The chlorophyll in the leaf captures sunlight and uses it to convert carbon dioxide and water into glucose and oxygen.
Leaves also facilitate gas exchange, allowing the plant to take in carbon dioxide for photosynthesis and release oxygen as a byproduct.
Through tiny openings called stomata, leaves release excess water in a process known as transpiration. This helps maintain the plant's water balance and facilitates the transport of water and nutrients from the roots to the rest of the plant.