Chloroplast
Chloroplasts are plastids, membrane-bound organelles, that conduct photosynthesis in plant cells. They use chlorophyll, contained in disc-like thylakoids, to capture, convert, and store sunlight in ATP and NADPH and free water in cells. The ATP and NADPH would go on to convert carbon dioxide into organic molecules in light-dependent reactions, also known as the Calvin cycle.
Animals lack chloroplasts. As such, one prerequisite for Animal Kingdom citizenship is a lack of chloroplasts.