Matter is constantly cycled between living and nonliving parts of the environment. Processes like photosynthesis and respiration allow the carbon cycle to regenerate needed substances by recycling Earth's atoms. A diagram of the carbon cycle is shown. Each arrow represents a process in the cycle. Which explanation best describes the process that occurs at the arrow marked B?
A. Plants use carbon dioxide from the atmosphere in the process of photosynthesis to produce glucose
B. Plants release carbon dioxide into the atmosphere in the process of photosynthesis to produce glucose
C. Plants use carbon dioxide from the atmosphere in the process of cellular respiration to convert glucose to ATP energy
D. Plants release carbon dioxide into the atmosphere in the process of cellular respiration to convert glucose to ATP energy