The carbon cycle is similar in every ecosystem, on this occasion we will use a template forest. As is a cycle we will start with respiration, plants, animals, and soil microorganisms release carbon dioxide into the atmosphere, (in this step we can include human pollution such as factories or burning wood) after this, a part of the carbon dioxide is reabsorbed by plants by photosynthesis, we call this step carbon fixation. When the plant is consumed by animals this carbon integrates into animals, also when living organisms (plants or animals) die, decay, and integrate into the soil, here in the process of decomposition there is a new release of carbon into the atmosphere by the action of microorganisms. If we assume that in this template forest there is a lake nearby we can include a gas exchange with water; carbon dioxide is released by water and at the same time, some carbon dioxide dissolves into the water. There are of course living organisms in the water that also contribute, nonetheless, that is another ecosystem that we are not analyzing here. Finally, as we can see is a cycle, carbon dioxide is released by organisms and reabsorbed by others, in the process some is fixated into soil other in the water and some more remains in the atmosphere.