Nitrogen Cycle 

A. the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

B. a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from nutrients into ATP

C. biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes.

D. the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth.