The image shows that the plants need Sunlight,C02, and water to make food or Photosynthesis.
In the process of Respiration some of the C02 is released back into the Atmosphere.
In the Hydrosphere the plants and animals die they decomposed in the hydrosphere which is turned into the C02 the C02 is spread around to the atmosphere to the tiniest organisms in the water.
When a fire is burning it also releases C02 into the atmosphere this is called "Combustion".
When a plant or animal has died they will decompose and it breaks down the body to release the C02 back into the Biosphere or the plant or animal will layer over sedimentary to be made into fossil fuel.
After Photosynthesis animal will use the oxygen and the plant to survive and the animal will release the C02 and back to a random plant to use again for photosynthesis.