Carbon atoms, just like this one, start their journey in the atmosphere in the form of carbon dioxide gas (CO2)
Later, the carbon atom is removed from the atmosphere through a process call photosynthesis. Photosynthesis is a process preformed by plants where they take CO2 from the air, to produce glucose and oxygen. The glucose is used to store energy for the plant and the oxygen is released into the atmosphere
Soon, through the process of respiration, the atom will transfer into an animal organism.
Once the animal organism dies it will become a part of the Lithosphere (along with the atom) by being broken down by decomposers. The process taking place is called decomposition.
The CO2 atom will then return to the atmosphere again through the long process of combustion!
Unfortunately, humans have burned so much fuel over the past few years that there is about 30% more carbon dioxide in the air today than there was about 150 years ago. Humans have thrown off the natural balance of the carbon cycle and more greenhouse gases such as carbon dioxide are in our atmosphere causing our planet to become warmer.
Eventually the CO2 atom will be soaked up by a body of water as it moves through the atmosphere.