Increase atmospheric carbon dioxide negatively affects coral
     Increase atmospheric carbon dioxide negatively affects coral reefs by:  Select one:  a. increasing photosynthesis by symbiotic algae  b. decreasing photosynthesis by symbiotic algae  c. increasing acidity of ocean water  d. decreasing acidity of ocean water  Refer to Infographic 22.7. Use the infographic to describe the general trend of atmospheric carbon dioxide (Co_2) levels from 1750 to the present  Select one  a. The graph shows a gradual increase from 1870 to 1960 followed by a more dramatic increase from 1960 to the present  b. CO_2 levels were measured indirectly from the ice core by looking back in time at the annual layers of ice in the core and liberating gas from bubbles trapped within the ice to measure CO_2, levels in the atmosphere at the time the air was trapped  c. A only  d. Both A and B are correct 
  
  Solution
Carbon dioxide increase pH of water and makes it more acidic so corals cannot obtain calcium carbonate to maintain there skeleton so answer is it increases acidity of water
Next question I guess both are correct

