Nutrient Cycles

Form in which carbon exists in the atmosphere

Process that removes carbon dioxide from the atmoshere

Process that produces carbon dioxide

Three processes in plants and animals that return carbon dioxide to the atmosphere

Process during which fossil fuels release carbon dioxide in the atmosphere

Gas released into the atmosphere during photosynthesis

(a)  

Gas absorbed from the atmosphere during respiration

Process during which lightning converts nitrogen gas into nitrates in the soil

Organisms responsible for most nitrogen fixation

(a)  

Process during which dead organic material is broken down to release ammonia