How Plants Make Food
Unlike animals, plants make their own food. The process is called photosynthesis, and it happens mostly in the leaves.
A plant needs three things for photosynthesis: sunlight, water, and carbon dioxide. Roots soak up water from the soil, and the water travels up the stem to the leaves. Carbon dioxide is a gas in the air. It enters the leaf through tiny holes that are far too small to see without a microscope.
Inside the leaf, cells hold a green substance called chlorophyll. Chlorophyll captures energy from sunlight. The plant uses that energy to turn water and carbon dioxide into sugar. The sugar is the plant's food. It gives the plant energy to grow, and some of it is stored in roots, stems, fruits, and seeds.
Photosynthesis makes something else, too. As the plant makes sugar, it lets oxygen out into the air through the same tiny holes. Animals, including people, need oxygen to breathe.
So plants feed themselves, and they help every animal on Earth. They give us the oxygen we breathe, and they are the starting point of most food chains.