Based on your description, it sounds like the diagram is likely illustrating the process of photosynthesis and cellular respiration, which involve specific gases and compounds. In the context of these processes, the most appropriate labels would typically be:
- Photosynthesis uses carbon dioxide and water to produce glucose and oxygen.
- Cellular respiration uses glucose and oxygen to produce carbon dioxide and water.
Therefore, if we are looking for correct labels for components related to these processes, the correct response would be:
1-carbon dioxide; 2-water
This indicates that during photosynthesis, carbon dioxide (1) and water (2) are essential reactants.