The given image is of carbon-dioxide cycle in nature. The plants use atmospheric CO₂ in photosynthesis to prepare food. The food is consumed by humans and animals which breathe out it (CO₂) and excrete out waste products which mixes in the soil. Plants also respire-intake oxygen and exhale CO₂. The dead and decaying matter forms fossil fuels overtime which is used in industries. These industries emit CO₂ once fuel is burnt. Thus, the circled arrows are representing how CO₂ is released back to atmosphere.
