The carbon atom in the carbon cycle is absorbed by the sugar cane plant during photosynthesis, released as sugar, subsequently fermented by yeast into ethanol, and eventually returned to the atmosphere as carbon dioxide through combustion or respiration.
In the carbon cycle depicted by the given diagram, the journey of a carbon atom begins with its absorption by the sugar cane plant during the process of photosynthesis. The plant utilizes sunlight to convert carbon dioxide into sugar, acting as a carbon sink. The sugar, representing stored carbon, is then subject to fermentation by yeast, leading to the production of ethanol.
This step introduces carbon back into the cycle. Subsequently, when ethanol undergoes combustion or is respired, carbon dioxide is released, completing the cycle as the carbon atom returns to the atmosphere. This intricate process highlights the dynamic interplay between living organisms and the atmosphere, emphasizing the continuous exchange of carbon in various forms.