The air gets changed inside their bodies. When they breathe the air out again there's something called carbon in it. Animals cannot use their air again. But plants need carbon. The plants trade fresh air for the carbon they need.
Plants make food from carbon and water.
They use sunlight for this work, just as a machine uses petrol to keep running. The plants store the food they make inside themselves. Many animals eat plants and then the animals' bodies store up the food that was in the plants. A honeybee collecting pollen and nectar from the flowers of the Greater Kyllinga. The larvae of the thrips found on the inflorescences are red while the adults are black.