There is a distinct oscillation of CO2 during each year as CO2 is added to the atmosphere each winter or removed from the atmosphere each summer.

Question

Explain what specific cellular processes lead to these changes in CO2 level.
You must explain what causes CO2 to be released to the atmosphere by the biosphere, and what causes CO2 to be removed from the atmosphere.

My answer: Carbon dioxide has a very important role in the plants entire process of photosynthesis. Plants release carbon dioxide and it is observed that when the carbon dioxide gas concentration is higher in the atmosphere there is an increased rate of photosynthesis with low rate of water loss.
There is always a big difference between the natural carbon dioxide level and the compulsory expulsion of carbon dioxide into the atmosphere. Likewise there is also another condition where a loss of carbon dioxide level occurs. One reason is the antroprogenic activity of humans which causes this. Burning of fuels specially fossil fuels causes removal of carbon dioxide from atmosphere where much other toxic gases may accumulate.
Recent studies still suggest that the unexpected higher levels of carbon dioxide is still due to the human activity

Please let me know if you think i have answered to the question correctly and if not what i should include. Thank you people

Answer 1

also should i include this: During the summer when plant life thrives the concentration drops, this is because the plants are "breathing" in the CO2, each fall as the vegetation dies off and decomposes some, (not all) of the sequestered CO2 is released back into the atmosphere. Also, while the majority of plant life is dormant during the winter other processes which create CO2 have a change to "catch up".