Answer:
When the level of release of carbon dioxide during respiration and use of carbon dioxide during photosynthesis this results in a compensation point. At compensation point the net available carbon dioxide to phototrophs becomes zero. As, carbon dioxide is the chief ingredient for photosynthetic products like glucose and oxygen. These products are used up during the process of respiration. When the rates of two processes photosynthesis and respiration becomes equal. Phototrophic organisms will not be able to compensate for lack of carbon dioxide levels. Phototrophs will not be able to produce their food in the form of glucose and hence will not be able to respire too. This will result in lack of overall available food from phototrophs and lack of available oxygen for respiration. This will result in decline of organisms on earth.