Photosynthesis is the process in which light energy of the sun is converted to chemical energy. The oxygen so released is used in the respiration process to break down complex molecules and releases energy in the form of ATP molecules.
Thus, positive reinforcement occurs when a behavior is encouraged by rewards. If a child enjoys candy and cleaning the room is the desired behavior, the candy is a positive reinforcer (reward) because it is something that is given or added when the behavior occurs. This makes the behavior more likely to recur.
A general ballpark how one can predict the way how evolution will work in the future would be by thinking about the requirement of a certain area or environment and which changes would be necessary and relevant for any organism to thrive with its new changes.
This could help people speeden up this process by enabling organisms to develop such traits faster, as well as ourselves.