Ken wrote a few steps to describe how carbon circulates between the atmosphere and living organisms. step 1 is missing. step 2: plants use carbon dioxide to make glucose step 3: plant-eating animals consume the glucose present in plants step 4: animals exhale carbon dioxide which of the following best describes step 1? a. carbon enters the atmosphere as carbon dioxide from respiration and combustion. b. dead animals are buried and form fossil fuels, which produce glucose on combustion. c. dead animals decompose and recycle the carbon in the form of oxygen and water vapor. d. carbon dioxide in the atmosphere is converted into glucose by animals during respiration.