Pass 1: culture a huge amount of spinachs that pull co2 out of the air
Pass 2: distroy this plants releasing co2 again in the air to obtain chloroplasts from the upper half of the creature. Set free again the co2 saved in roots. (Alternatively pick only leaves from the spinach).
Pass 3: use this chloroplasts to recover a part of the co2 released in the pass 2
Pass 2: distroy this plants releasing co2 again in the air to obtain chloroplasts from the upper half of the creature. Set free again the co2 saved in roots. (Alternatively pick only leaves from the spinach).
Pass 3: use this chloroplasts to recover a part of the co2 released in the pass 2
Pass 4: ... D'oh!