What increases the amount of carbon dioxide in the atmosphere? 

A)  respiration 
B)  less forest fires 
C)  photosynthesis 
D)  recombination

Respiration is a natural process in which living organisms release carbon dioxide into the atmosphere as they exhale. This increase in carbon dioxide levels contributes to climate change. Less forest fires and photosynthesis both result in a decrease in carbon dioxide levels in the atmosphere, whereas recombination is not directly related to carbon dioxide levels.