The relationship between photosynthesis and respiration can be best described as:
1. Photosynthesis and respiration are reversal of each other in biochemical pathways.
2. Photosynthesis stores energy in complex organic molecules, while respiration releases it.
3. Respiration occurs only in animals and photosynthesis occurs only in plants.
4. Respiration results in formation of ATP but photosynthesis can only use them.