Final answer:
The carbon cycle describes the exchange of carbon between the Earth's biosphere and atmosphere through photosynthesis, respiration, decomposition, and combustion.
Step-by-step explanation:
The carbon cycle is a fundamental biogeochemical cycle where carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Photosynthesis by plants and other photosynthetic organisms captures carbon dioxide from the atmosphere and converts it into organic carbon compounds, such as glucose, which are used to build plant biomass. This process not only lends energy to the ecosystem but also cleans the atmosphere by reducing carbon dioxide levels.
Respiration is the process by which living organisms, including plants and animals, convert organic carbon back into carbon dioxide, which is then released into the atmosphere, thus completing a part of the cycle. Furthermore, when living organisms die, the process of decomposition returns carbon to the Earth as it breaks down organic matter. Combustion of organic matter and fossil fuels dramatically increases the amount of carbon dioxide that goes into the atmosphere, having a significant impact on the global carbon cycle and contributing to climate change.