Answer:
1. Before: carbon dioxide After: Oxygen
2. Oxygen
3. Chloroplast
The answer is; YES
All organisms share one common ancestor in the beginning of life. Different species have branched at different times from common ancestors hence he evolutionary tree looks like tree called a cladogram. The nodes represent the common ancestry while branches depict divergence. Therefore even fruit flies and the fruit bats even though they do not belong to the same species shared a common ancestor at one time in history.
If a scientist is planning to carry out such an experiment it wouldn't be appropriate to go and test this right ahead without any serious protection. It is always advised that scientists first collect data after they've created their initial hypotheses and read the required literature.
This is true they are the products of photosynthesis and the reactants for aerobic respiration.