Carbon cycle
The natural Carbon Cycle describes the way of energetic interaction of plants and animals.
The CO2 is consumed by the food plants. This is part of the carbon cycle, assumed that all food is grown by food plants in the colony. All hydrocarbon intake is exhaled as CO2 after digestion and metabolizing. Exactly the same amount of CO2 is inhaled by the food plants and metabolized to hydrocarbons. The carbon is neither created nor destroyed anywhere in the cycle.
