Photosynthesis is the process of using sunlight to synthesize nutrients from carbon dioxide and water, most commonly utilised by real plants.
Most plants in the Creatures series do not truly photosynthesise, but are programmed to not grow in areas without light. The grass in the C3 norn terrarium is a rare example of a photosynthesizing plant. On the other hand, creatures have been genetically altered to photosynthesize. Calvin norns and plant norns photosynthesize.