Carbon cycle, one of the most important elements that make up the structure of living things in an ecosystem carbon. Carbon is found in the structure of all organic compounds in living things.
Earth is important warehouses;
Atmospheric CO2In the waters of CO2 and HCO3-Land, usually coal, is the structure of the oil and limestone.<span>Photosynthesis by plants using airborne CO2 and O2 is converted to organic compounds. By participating in CO2 carbon all live in the structure of the building is used as a raw organic food energy and structure. In respiratory events again returned to the atmosphere as CO2. If a portion of the carbon is deposited on the ground layer mineral or dead plants and animals through the soil into the organic waste. Here are separated by saprophytes live or coal goes back into the atmosphere through the use of fossil fuels such as oil. However, excessive use of fossil fuels in the atmosphere the CO2 greenhouse effect climate change will bring about in the world, raises a few degrees increase and the consequent danger of melting glaciers at the poles of the temperature.</span><span />
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The respiratory system contains the lungs, so the answer is C. Hope this helps.