Carbon is an element that is required for life.
All plants and animals contain carbon. The radioactive half-life for this emission is 5,730 years. They retain the carbon and oxygen, and exhale CO 2 as waste. In this way, both plants and animals are constantly exchanging carbon and oxygen with that in the atmosphere. While they are alive, their bodies contain the same fraction of the three carbon isotopes as does the atmosphere, but at death, respiration ceases and the exchange stops.