Final answer:
Carbon dioxide is produced by decomposition of organic matter, cellular respiration by living organisms, and combustion of organic materials, therefore, the correct answer is 'd) All of the above'.
Step-by-step explanation:
The process that produces carbon dioxide (CO2) includes decomposition, cellular respiration, and combustion. During decomposition, dead organisms and other organic materials break down, releasing CO2 into the atmosphere. Cellular respiration is a process where cells break down glucose in presence of oxygen, producing CO2, water, and energy, as shown by the equation C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy. Lastly, combustion of organic material, like fossil fuels, results in the release of CO2.