Answer: There will be more of carbon dioxide.
Explanation: In photosynthesis, plants use carbon dioxide and water in the presence of sunlight to produce glucose and oxygen.
If plants stop photosynthesis, there will be more of carbon dioxide and less of oxygen because large amount of oxygen is being produced by plants during photosynthesis. The resultant effect is that there will be shortage of oxygen for both plants and animals for cellular respiration and there will also be shortage of food for the generation of energy in cellular respiration. This means that there will be no life on earth as all living organisms will die of due to the fact that oxygen will be used up and there will be no energy to sustain life as plants no longer synthesize foods.