The leaf is the main food-making part of almost all plants. Garden flowers, grasses, shrubs, and trees depend on their leaves to make food for the rest of the plant. So do many other plants, including ferns, vegetables, vines, and weeds.

Each leaf is a little food factory. It captures energy from sunlight and uses it to make sugar out of water from the soil and carbon dioxide, a gas in the air. This sugar is changed to many other chemical substances. These substances become the food that provides plants with energy to grow, to produce flowers and seeds, and to carry on all their other activities.

Plants store the food made by leaves in their fruits, roots, seeds, stems, and even in the leaves themselves. Without this food, plants could not live. In addition, all the food that people and animals eat comes either from plants or from animals that eat plants.