Explain how carbon atoms can move from co2 in the air into an organic molecule inside a plant and then back to co2 in the air.

As we know that the plants is universal producer.Plant absorb CO2 from atmosphere by the help of photosynthesis from where plant make glucose ,oxygen and energy and then plant exhale O2 but in plants there is another process is going on called respiration which exhale same amount of CO2 as consumed in photosyntesis and in autumn the leaves fall on the soil which on later decomposed and release carbon dioxide this whole  cycle is called carbon cycle !!

The answer would be simply interphase and mitosis